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EEVblog => EEVblog Specific => Topic started by: EEVblog on November 14, 2014, 11:48:25 am

Title: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 14, 2014, 11:48:25 am
Dave investigates two very serious issues with jitter on the Rigol DS1000Z series oscilloscopes, including the DS1104Z and new DS1054Z
Some sort of modulated sampling/trigger jitter problem at 5 microsecond intervals (the "5us jitter problem"). And severe jitter with the AC coupled trigger mode, a problem which is also present on the DS2000 series scopes as well.

NOTE: So many people have been confusing AC trigger coupling with AC input coupling people will be more familiar with. This issue has *nothing* to do with AC input coupling, it is AC trigger coupling!

Mads from EcProjects found the 5us jitter problem:
https://www.youtube.com/watch?v=dHQ4MsMFJTk#t=172 (https://www.youtube.com/watch?v=dHQ4MsMFJTk#t=172)
https://www.youtube.com/user/EcProjects (https://www.youtube.com/user/EcProjects)

! Private video (https://www.youtube.com/watch?v=kcOdzFaIYNE#)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: frogmaster on November 14, 2014, 12:11:24 pm
Just checked, I have the same AC trigger problem with my DS1054 that shipped last week. 5us seems fine here.  :-//

EDIT: Nevermind, on a second the look 5us problem's here too. 04.01.SP2, Board 0.1.1
EDIT: coupling -> trigger ::)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: hans on November 14, 2014, 12:15:02 pm
As I said on EcProjects video, my DS1074Z from spring this year does not suffer the 5us trigger problem.

I measured a 25MHz oscillator, so if it would be a beat frequency you may see the same thing at 4us (-20% period).. nope nothing there.

I still run v2 firmware (SP5). That firmware version doesn't show the board version, but I assume it's a very early-on model.

It seems like the AC coupling issue is also present on this older firmware version.
The LFR does the same thing.

In fact, I think I can do better. If I put the scope channel  to AC coupling as well (so it triggers when it zero-crosses), I get this weird artifact:
(https://dl.dropboxusercontent.com/u/207647/DS1Z_QucikPrint4.png)

I'm pretty darn sure this oscillator & board is OK; because it runs a 100Mbit ethernet phy at full speed without any hiccups. (And also it shows no sign of trouble on all DC coupling)
edit: The internal function generator does the same, so it's in the scope AC triggering. The artifact changes with frequency quite drastically, but even at 5MHz the triggering is very jitterish.

I have recorded the frames using the record function. The "jitter" on this image repeats every 8 cycles (coincidence 2^3?). The first 3 frames are clean. On the 4th the waveform jumps 3ns to the left and gets progressively worse over 5-7 frames. On the 8th it jumps back. This repeats on and on..

I also noted that the LFR/AC does not have a trigger level pointer next to the screen side, but it does show a "voltage" in the right hand corner. What is that all about? It seems like the AC-only triggering is off by quite a bit.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: robbak on November 14, 2014, 12:23:53 pm
Are either problems affected if your signal is properly terminated? Especially the AC triggering - I can easily see how adding an extra capacitor could cause... well, anything!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 14, 2014, 12:26:49 pm
I have recorded the frames using the record function. The "jitter" on this image repeats every 8 cycles (coincidence 2^3?). The first 3 frames are clean. On the 4th the waveform jumps 3ns to the left and gets progressively worse over 5-7 frames. On the 8th it jumps back. This repeats on and on..

Interesting analysis, thanks.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: coppice on November 14, 2014, 12:40:05 pm
What do the settings on the Rigol generator mean? The way generators specify offset varies. Is 5V p-p with 0V offset a +2.5V to -2.5V square wave? The graph the the bottom of the screen has a faint line at the top of the square wave like that might be the 0V indicator. If it is, I am not surprised the scopes mistrigger when switching from DC coupled triggering to AC coupled.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: hans on November 14, 2014, 12:47:31 pm
It seems now that the period has changed on a few subsequent records, so I neither have a clue what's going on :-//
What I can see is that the trigger drifts away. There are several good triggers, and then it snaps out by quite a bit and creeps up. After a few frames it jumps back - although that seems to vary now unfortunately.

It also occurs when I pick a large timebase (1us/div) and then zoom in.
Even with a trigger holdoff of 1s it jitters. |O

If I change the impedance of the Rigol function generator to HighZ or 50 ohm it does not make any difference to the glitch I have displayed.  Amplitude 1V and offset 0V on my signal, so the signal swings +/- 500mV.

Could very well be a digital problem because I recall from some source that the triggering is all-digital in these Rigol.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: JimmySte on November 14, 2014, 12:50:04 pm
Well I just did a quick test on my DS2072 and I couldn't reproduce the errors Dave found...
Although I was using the internal 1kHZ square wave.

(https://dl.dropboxusercontent.com/u/4358943/DS2_QuickPrint36.bmp)

(https://dl.dropboxusercontent.com/u/4358943/DS2_QuickPrint37.bmp)

(https://dl.dropboxusercontent.com/u/4358943/DS2_QuickPrint38.bmp)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: womai on November 14, 2014, 12:55:49 pm
On Dave's video it looks like the jitter is discrete, i.e. only a finite number of separate timing positions. This would match what hans observed. What I also think I am seeing is that the number of discrete positions is twice as high on the 2000 series scope than it is on the 1052z series scope. At the same time, the difference in maximum sample rates is also factor of 2 (2 GSa/sec vs 1 GSa/sec). All this for me points to a digital (FPGA) issue. AFAIK the Rigols interleave several ADCs to get the maximum sample rate. Maybe the FPGA or firmware messes up the phases to the ADCs (or uses incorrect cal values for the phases) so their alignment is off?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: German_EE on November 14, 2014, 01:07:06 pm
Gut feeling tells me that the 5uS jitter issue is a hardware problem, most modern scopes take a 10 MHz signal then multiply it up using PLL chips and I think we are seeing a PLL problem here. There is something about ADC scopes and jitter that I have yet to conquer. I have a Picoscope 3000 series and the jitter on that was so bad that I built my own separate trigger circuit and fed that into external trigger.

Dave, your function generator should have a sync output or something like it. What happens when you drive a Rigol scope off an external trigger?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: electronic_eel on November 14, 2014, 01:23:25 pm
Just tested my MSO4000 with firmware 00.02.02 and a 20 MHz signal:

Edit: seems I didn't check thoroughly enough, see below.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Supercharged on November 14, 2014, 01:46:15 pm
I can't reproduce either errors on my DS1074Z-S (Software version 00.02.03.SP5), by using the internal Function generator.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Towger on November 14, 2014, 01:54:53 pm
Can't reproduce it on my DS1104Z with 00.02.01.SP1 firmware. Trace is slightly noisy no matter the offset, but that probably the source. Only difference is I don't have a FG capable of 20Mhz, if that makes any difference!

Edit: Tried again with a proper function generator (less noise) at 2Mhz and could not reproduce it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TheBay on November 14, 2014, 02:10:33 pm
I'm not 100% familiar with my DS2072 as it's my first DSO (Used only CRO's) Using the internal square wave can someone tell me the quickest way to check this.

Cheers :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 14, 2014, 02:15:28 pm
Did you look at the trigger-out?
This may give some clues as to whether it's a hardware or software issue
 
Having said that I'm not sure I've ever used AC triggering...

Shouldn't happen, but I can't see this being a deal-breaker given the general performance and value for money.
 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: firewalker on November 14, 2014, 02:16:24 pm
Just tested my MSO4000 with firmware 00.02.02 and a 20 MHz signal:
  • No jitter at 5µs
  • No jitter on an AC coupled trigger

I can't reproduce either errors on my DS1074Z-S (Software version 00.02.03.SP5), by using the internal Function generator.

Hardware versions?

Alexander.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: frogmaster on November 14, 2014, 02:20:19 pm
I can't reproduce either errors on my DS1074Z-S (Software version 00.02.03.SP5), by using the internal Function generator.

Neither do I with my DS1054. But I found something else I can do with the internal function gen: freeze or crash my scope. Can't really figure out how to reproduce. What I did was inspecting the internal 1kHz function with AC triggering, occasionally zooming in and out (pushing things to the limit basically). Finally, when I tried to display the pulse width the scope crashed. The first time I did this I saw some kind of junk on the display, just random pixels. (I actually have seen that before- and I only have it for a week now.) It didn't react to any inputs either.
I rebooted the whole thing and tried to reproduce the error. No junk on the screen this time but it did freeze again. Maybe it's just my particular scope but I'm curious though if anyone else has experienced these kinds of problems.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rolycat on November 14, 2014, 02:35:04 pm
(Edited to show AC-coupled trigger jitter)

I can confirm that my 1054Z appears to have a serious problem with the 5us jitter issue:
(http://i.imgur.com/TsAENDq.jpg)

(http://i.imgur.com/GUMfu26.jpg)

AC coupled triggering also showing nasty jitter:
(http://i.imgur.com/hzxma90.jpg)
 
Signal is a 5MHz, 5V P-P square wave from a Rigol DG1022U.

Version:
(http://i.imgur.com/VSt2fHX.jpg?1)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 14, 2014, 02:39:37 pm
MSO4054 at various delays and beyond, sorry for the ultra crappy webcam footage.  (firmware = 2.02.SP1, hardware version = 1.3)

20Mhz, square, 5Vpp, AC/DC coupling has no effect.

MSO4054 delay jitter (https://www.youtube.com/watch?v=2-mQ6TWP13A#ws)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 02:45:32 pm
Same here... Flippen hope this is just firmware...

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nuno on November 14, 2014, 02:53:48 pm
I see none of the 2 problems the trigger AC cooupling jitter issue on my DS1104Z-S, using the internal sig gen.
Sw version is 00.04.00
No mention of hw version.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jucole on November 14, 2014, 02:56:25 pm
on Monday I bought an older Instek 2202, but almost went for a Rigol;  i'm so glad I didn't get a Rigol!!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Lukas on November 14, 2014, 02:57:27 pm
I'm sure they can fix this with a FPGA update. The DS1054Z doesn't have a trigger comparator, so they have to do all the triggering on the acquired data, which works surprisingly well. (Wondering what happens if you turn on all four channels). For AC triggering they have to digitally highpass-filter the data before finding the trigger instant. I guess they messed up the filter. The 1052E uses a classic analog trigger, so they don't have this issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 03:05:55 pm
Is it possible to downgrade the firmware on the DS1000Z range? Or is the firmware version bound to the hardware version?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: H.O on November 14, 2014, 03:13:09 pm
Tried it on my DS4k, 20MHz square wave, 50% generated with a DG4162:

AC or DC coupling doesn't seem to make any difference.

EDIT: Firmware 02.02.01.01
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jit ... + Broken Freq.
Post by: EE-digger on November 14, 2014, 03:16:25 pm
On an MSO1104Z, I saw serious jitter on a 100MHz, clean sine wave.  It seemed to happen after having all 4 channels active and then turning off the other 3.

Nothing would make the jitter go away until I pressed AUTO.  After AUTO was done, I had to turn off channels 1-3 since my sine was on 4.  Now the jitter was gone.

Along with this, I discovered that the frequency counter is BROKEN.  Again, with a clean sine (57.000MHz, 90.000MHz), the frequency will read high or low, by a huge error, as you adjust the trigger level, all the while the sine remained cleanly triggered.

The frequency appears to be correct only when your trigger line is close to the zero crossing of the waveform.

Den
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: olewales on November 14, 2014, 03:25:47 pm
My results attached.

DS1054Z
SW: 00.04.01.SP2
Board: 0.1.1
Date of calibration (on cal certificate): 04-Sep-2014

Let me say that I don't consider this that big of an issue. Good indication of this is that nobody have noticed any of this for a long time. That's especially true for AC trigger issue which seems to also be present on DS2000 series. For me its just another bug that I need to be aware of as a user. Maybe it would be a good idea to start a thread with list of known bugs in DS1000z series. I could contribute to that (rise/fall time rate measurements broken)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 03:28:06 pm
My results attached.

DS1054Z
SW: 00.04.01.SP2
Board: 0.1.1
Date of calibration (on cal certificate): 04-Sep-2014

Let me say that I don't consider this that big of an issue. Good indication of this is that nobody have noticed any of this for a long time. That's especially true for AC trigger issue which seems to also be present on DS2000 series. For me its just another bug that I need to be aware of as a user. Maybe it would be a good idea to start a thread with list of known bugs in DS1000z series. I could contribute to that (rise/fall time rate measurements broken)

It seems there are 2 flavours of the jitter issue. Yours is not so bad (I could live with it) but mine is seriously bad, like some others have. :(
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EE-digger on November 14, 2014, 03:32:07 pm
When I had the jitter, no scope setting would make it go away.  Reminds me of Windows, when all "accessible" parameters are correct but it doesn't do something correctly.

Maybe a registry problem :) :) :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Muttley Snickers on November 14, 2014, 03:36:41 pm
Wow, a newly found feature on the Rigol 1000z series.

Bonus Epileptic Fit Generator.   :-DD

Muttley


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 14, 2014, 03:51:10 pm
Would be interesting to compare results with internal vs. external function gen - something like leakage of an internal clock to the analogue trigger circuitry would probably have a different effect depending on whether or not it was synced to the scope's clock.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: SiC on November 14, 2014, 04:01:09 pm
On my DS1074Z soft-upgraded/unlock to 100MHz and using the internal source (set at 20MHz), I don't see the 5uS jitter issue at all. However the AC coupling jitter problem is clear as day. 500nS hold-off on AC coupling produces some weird effects too.

Software revision 00.04.00.
Serial number DS1ZB16115xxxx.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xnaron on November 14, 2014, 04:03:47 pm
 Fingers crossed it can be fixed in firmware.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: XFDDesign on November 14, 2014, 04:06:11 pm
MSO4054 at various delays and beyond, sorry for the ultra crappy webcam footage.  (firmware = 2.02.SP1, hardware version = 1.3)

20Mhz, square, 5Vpp, AC/DC coupling has no effect.

MSO4054 delay jitter (https://www.youtube.com/watch?v=2-mQ6TWP13A#ws)

Balls. Even the 4000 series has the issue. I've been wanting to get one.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 04:12:36 pm
MSO4054 at various delays and beyond, sorry for the ultra crappy webcam footage.  (firmware = 2.02.SP1, hardware version = 1.3)

20Mhz, square, 5Vpp, AC/DC coupling has no effect.

MSO4054 delay jitter (https://www.youtube.com/watch?v=2-mQ6TWP13A#ws)

Balls. Even the 4000 series has the issue. I've been wanting to get one.

Thanks for the comment, I never watched the video, and even 90% thru it I though everything was hunky dory, but holy batshit! that is some wack shit going on there!   :-BROKE
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 14, 2014, 04:15:49 pm
Can confirm my DS1054Z looks exactly like rolycat's with DC triggering, 5us offset.

FW 4.02.SP3
HW 0.1.1

External square wave signal from DG4000, 50ohm termination.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Döner Hawaii on November 14, 2014, 04:18:42 pm
Can't confirm the 5µs trigger issue on my MSO1104Z-S.
But the AC trigger jitter is also there.  :(

Tested by measuring the internal signal generator with one of the probes.
Software Version 00.04.00

Images attached.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nuno on November 14, 2014, 04:19:19 pm
I see none of the 2 problems on my DS1104Z-S, using the internal sig gen.
Sw version is 00.04.00
No mention of hw version.

Ok, I correct myself, mine has the AC coupling trigger jitter. I actually interpreted the problem wrongly, thinking it was the input channel coupling having the issue. I admit I had never noticed that there was a trigger coupling mode :o ...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 04:23:59 pm
Can't confirm the issue on my MSO1104Z-S.

Tested by measuring the internal signal generator with one of the probes.
Software Version 00.04.00

Images attached.

What hardware version? If 0.1.1 like the rest of us, perhaps it is merely a firmware bug :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: SiC on November 14, 2014, 04:26:31 pm
Can't confirm the issue on my MSO1104Z-S.

Tested by measuring the internal signal generator with one of the probes.
Software Version 00.04.00

Images attached.

What hardware version? If 0.1.1 like the rest of us, perhaps it is merely a firmware bug :)

How do you determine the hardware version?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Döner Hawaii on November 14, 2014, 04:27:56 pm
What hardware version? If 0.1.1 like the rest of us, perhaps it is merely a firmware bug :)

Sorry, misunderstood the problem.
I did not realize that the ac coupling jitter appears when the trigger is coupled.

Corrected my reply.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 04:34:13 pm
What hardware version? If 0.1.1 like the rest of us, perhaps it is merely a firmware bug :)

Sorry, misunderstood the problem.
I did not realize that the ac coupling jitter appears when the trigger is coupled.

Corrected my reply.

The AC couple triggering is minor to me. At least you have the DC workaround.

The 5us jitter issue is more of my concern which yours dont seem to show.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 14, 2014, 04:34:42 pm
What hardware version? If 0.1.1 like the rest of us, perhaps it is merely a firmware bug :)

Sorry, missunderstood the problem.
I did not realize that the ac coupling jitter appears when the trigger is coupled.

Corrected my reply.
Could it be that it accidentally switches in HF and/or noise reject?


Also, assuming there is an issue with an internal clock influencing trigger level, a few things that may shed some light :
Using an external sig-gen, vary the frequency very slightly by a few Hz - see if there is any phasing type effect. This could be why some people see different results (slight differences in xtal freq), and don't see it from the internal siggen.
Try different waveform risetimes  - do you get more jitter on a triangle compared to a square wave - it may be possible to quantify the amplitude of the noise. Also is it consistent across different vertical scale settings & signal amplitudes?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EE-digger on November 14, 2014, 04:41:38 pm
When I set an external Agilent source to 25MHz and 1Hz increment, I can adjust the frequency modulation of the jitter band to nothing.  At a 1Hz step away from "no band", I can watch the wave move left to right with a 1Hz period.

All the while, the right most wave remains stable and unaffected.

This is an MSO1104Z received in the past week, latest firmware.  Trigger is AC coupled.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Muttley Snickers on November 14, 2014, 04:42:30 pm
Out of curiosity,

Does anybody know what the going hourly rate is worth for freelance beta testers ?.

If you have already got one of these, then add this to your resume.

Muttley

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 14, 2014, 04:43:48 pm
Square/Sine/Triangle all produce the same amount of jitter for me, the slope of the rising edge doesn't seem to affect it.

Changing the frequency of the signal doesn't alter it either, that's the first thing i tried to rules out the possibility of sampling jitter from my function gen.

Also tried changing from edge triggering to slope to no avail.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EE-digger on November 14, 2014, 04:46:06 pm
Also note that the memory depth has a definite impact on the jitter band.

As I manually go from AUTO to full memory, the jitter goes from the smooth band to a sweeping movement, similar to a 1Hz offset I mentioned above.

Acts like an errant index into memory but not on DC :) .

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 04:46:42 pm
Out of curiosity,

Does anybody know what the going hourly
rate is worth for freelance beta testers ?.

If you have already got one of these, then add this to your resume.

Muttley

Its OK, I already have this on mine  ;D
Quote
Other affiliations:
 
United Federation of Planets (46379.1 - 46831.5)
 
Responsibilities:
 
- Cleaning plasma warp coils
- Assist in dylithium crystal alignment
- Replacement of bio-neural gel packs in the Jefferies tubes
 
Contact person: Jean-Luc Picard

Also note that the memory depth has a definite impact on the jitter band.

As I manually go from AUTO to full memory, the jitter goes from the smooth band to a sweeping movement, similar to a 1Hz offset I mentioned above.

Acts like an errant index into memory but not on DC :) .

That is why I enabled persistence on my screen caps.

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=118451;image)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: electronic_eel on November 14, 2014, 04:50:18 pm
MSO4054 at various delays and beyond, sorry for the ultra crappy webcam footage.  (firmware = 2.02.SP1, hardware version = 1.3)

20Mhz, square, 5Vpp, AC/DC coupling has no effect.

MSO4054 delay jitter (https://www.youtube.com/watch?v=2-mQ6TWP13A#ws)
Just tried it with exactly your settings on my MSO4000 and now I see it too. But I think it is a bit less on mine. FW=2.02.SP1, hardware version = 1.3. Seems like I didn't zoom in enough the first time.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tchicago on November 14, 2014, 04:54:01 pm
Can't confirm neither of these issues on my DS1104Z purchased this spring. Software version 00.02.03.SP5. Hardware version unknown, it is just not displayed on the sysinfo screen.

No jitter at AC coupling at any offset, and no jitter at DC coupling - tried multiple offsets, 0, 0us, 10us, 15us, fractionals of those.

Attached is a screenshot of 15MHz being fed directly from HP 33120A signal gen, shifted 5us from trigger point. The voltage shown is wrong of course because it is expecting the 10x probe divider instead of direct BNC-BNC cable.

There is other issue with this scope that drives me mad: a very slow response from the vertical offset knob. Does anyone know if there is any software update that would fix this problem?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 04:54:59 pm
Just tried it with exactly your settings on my MSO4000 and now I see it too. But I think it is a bit less on mine. FW=2.02.SP1, hardware version = 1.3. Seems like I didn't zoom in enough the first time.

Watch from 1:02 (https://www.youtube.com/watch?v=2-mQ6TWP13A#t=62) onwards. Nasty stuff.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Monsterhero on November 14, 2014, 05:07:42 pm
While I was trying the trigger issue on my DS2072, i noticed another bug.

With DC-Coupling there is a trigger-level marker, with AC-Coupling the trigge-level marker dissapears.
So it's more difficult to set the trigger correct.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 14, 2014, 05:10:29 pm
Also note that the memory depth has a definite impact on the jitter band.

As I manually go from AUTO to full memory, the jitter goes from the smooth band to a sweeping movement, similar to a 1Hz offset I mentioned above.
I don't think it does.

The memory depth seems to impact how many captures are used to generate the intensity grading. When you crank up the memory depth, obviously the scope is doing a lot more work to overlay 24Mpts captures instead of 12Kpts, so less captures are used to generate each frame and as a result you can observe individual captures jumping about instead of just a 'blur' of many many captures. Also, you can do a lot more 12Kpts captures in between having to update the display, than you can having to do 24Mpts captures. Even with zero dead time you can only capture 24Mpts @ 1GSa/s, 41.66 times a second which might even be less times a second than it actually updates the display. At 12Kpts you can do 83333 per second. Assuming it updates the display at 30fps that gives you almost 3000 captures to generate each frame, giving you a nice blurry image and increasing the chance of runt pulses etc being shown.

The same effect can be observed by deliberately sending the scope a jittery signal and changing the memory depth. It even works for low frequency signals.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: SiC on November 14, 2014, 05:10:59 pm
Can't confirm neither of these issues on my DS1104Z purchased this spring. Software version 00.02.03.SP5. Hardware version unknown, it is just not displayed on the sysinfo screen.

No jitter at AC coupling at any offset, and no jitter at DC coupling - tried multiple offsets, 0, 0us, 10us, 15us, fractionals of those.

Attached is a screenshot of 15MHz being fed directly from HP 33120A signal gen, shifted 5us from trigger point. The voltage shown is wrong of course because it is expecting the 10x probe divider instead of direct BNC-BNC cable.

There is other issue with this scope that drives me mad: a very slow response from the vertical offset knob. Does anyone know if there is any software update that would fix this problem?

Wrong coupling option. Try the AC coupling trigger mode.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 14, 2014, 05:15:40 pm
Another thought - is it the same on all channels? If different it may point to a layout/crosstalk issue.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: electronic_eel on November 14, 2014, 05:15:51 pm
Watch from 1:02 (https://www.youtube.com/watch?v=2-mQ6TWP13A#t=62) onwards. Nasty stuff.
Oh, yes I can see that too.

But when thinking about it - I'm not sure if all that is from the scope. It could also be the signal source.

I'm using an Agilent 33220A, the Jitter (RMS) is specified to be lower than "1ns + 100ppm of period".
Unfortunately the scope seems to be missing a jitter measurement function, so I used cursors & persistence and got about 4ns pp. Can't really measure RMS but I guess it is still more than the specs of the function gen would allow. So the scope is most probably the offender.

I'm using the internal timebase of the scope and don't have the external timebase option for the function generator so I can't sync them.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: electronic_eel on November 14, 2014, 05:18:54 pm
Another thought - is it the same on all channels? If different it may point to a layout/crosstalk issue.
On my MSO4000 it's the same on all 4 channels.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 05:21:32 pm
Oh, yes I can see that too.

Big difference between 4ns jitter on 5ms delay vs 20ns jitter on 5us delay though :(
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on November 14, 2014, 05:22:02 pm
I have to say Dave, that stack of scopes was awesome! I laughed out loud, great entertainment.

Maybe you can do a domino row with some old CRO's and let them this that would definitely get some views and of course hate mail. 

Two thumbs up.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 14, 2014, 05:25:53 pm
Another thought - is it the same on all channels? If different it may point to a layout/crosstalk issue.
Absolutely the same on every channel. The channels don't seem to jitter with respect to each other. Triggering off channel 2 and observing channel 1 produces the same results as triggering/observing channel 1.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: hans on November 14, 2014, 05:36:34 pm
When I set an external Agilent source to 25MHz and 1Hz increment, I can adjust the frequency modulation of the jitter band to nothing.  At a 1Hz step away from "no band", I can watch the wave move left to right with a 1Hz period.

All the while, the right most wave remains stable and unaffected.

This is an MSO1104Z received in the past week, latest firmware.  Trigger is AC coupled.
Likely because of the update rate.
At 1s trigger holdoff the scope only triggers once per second, but it replays the artifact at a very slow rate.
At full speed the scope does several thousand of updates per second (50ns seems to be the sweet spot in the v2 firmware - 30k wfms+), so you don't see how it dances around so well.


Can't confirm neither of these issues on my DS1104Z purchased this spring. Software version 00.02.03.SP5. Hardware version unknown, it is just not displayed on the sysinfo screen.

No jitter at AC coupling at any offset, and no jitter at DC coupling - tried multiple offsets, 0, 0us, 10us, 15us, fractionals of those.

Attached is a screenshot of 15MHz being fed directly from HP 33120A signal gen, shifted 5us from trigger point. The voltage shown is wrong of course because it is expecting the 10x probe divider instead of direct BNC-BNC cable.

There is other issue with this scope that drives me mad: a very slow response from the vertical offset knob. Does anyone know if there is any software update that would fix this problem?

The trigger needs AC coupling for it go berserk.
Also the artifact I have shown only settles in at >22.5MHz.  Lower than that and it looks identical to the AC triggering issue Dave showed, the triggering is jittering. A coincidence: it also happens at half 22.5MHz -> ~11MHz. There is a band where the artifact is present. Around 15MHz it's already gone.

It also seems to do that when there is no DC offset. When there is a DC offset, it looks like "normal jitter".
I also noticed that if I do set the trigger level higher, I can put it near the peak of the sine wave and the jittering stops. Actually it's around the point the built-in hardware frequency counter has no trigger to count the frequency anymore. Coincidence?
See here; AC trigger, point @ 400mV (top right corner):
https://dl.dropboxusercontent.com/u/207647/Amplitude%20800mV.png
Automatic measurements measure 800mVpp for a 900mVpp generated signal. It's probably a combination of both the scope and function generator that's slightly attenuated. Unfortunately the effect is not that strongly present at 12.5MHz. Notice there is no hardware frequency.
https://dl.dropboxusercontent.com/u/207647/Amplitude%20900mV.png
And the artifact is back, plus the frequency counter.. well sort of. If I were to increase the amplitude even more, it would come back.


I also notice that if the V/div setting I need to move the trigger level otherwise the waveform updating stays frozen. Wonderful.

It happens on any channel. Enabling 2 channels doesn't seem to make it worse or better - it's as bad.

The trigger OUT seems to jitter even with DC coupling; although thanks to the intensity grading it seems like the jitter band is smaller (about half) and more concentrated at 1 point. It also delayed by about 350ns.
AC trig out: https://dl.dropboxusercontent.com/u/207647/TRIGOUT%20AC.png
DC trig out: https://dl.dropboxusercontent.com/u/207647/TRIGOUT%20DC.png
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Arch on November 14, 2014, 05:42:20 pm
Hey,

I bought my ds1074z early this year
version 04.00
Doesn't display the board version unfortunately

I don't get the 5us issue but I do get the trigger ac coupling issue. At first I thought I had no issue but then I realized it wasn't the channel coupling.
I didn't even know this option existed until this video so I don't think it's a concern for me, at least for now haha  :-BROKE
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jnissen on November 14, 2014, 05:51:41 pm
Wonder if they are using a digital spread spectrum technique for the display electronics? Commercial guys use that to pass EMI/EMC compliance tests.  I could see a beat frequency issue that may have been missed. Any third party spread spectrum clocking sources on the board? Could be built into the asics as well.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 14, 2014, 06:02:28 pm
 :phew:

Everyone can calm down and rest easy for the weekend, the TDS 210 does not have this issue.

 :-DD

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 14, 2014, 06:07:01 pm
:phew:

Everyone can calm down and rest easy for the weekend, the TDS 210 does not have this issue.

 :-DD

I'll up you one and show my TDS360 does not have this issue  :-DD (Mostly because I think it not capable of doing it)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nixfu on November 14, 2014, 06:09:53 pm
If you have version 2.0 of the firmware please test.  Some people seem to be saying that version 2.x of the firmware does not show this issue, but version 4.x does.  If this can be confirmed it would be nice to know its a firmware issue and can be easily fixed.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: janengelbrecht on November 14, 2014, 06:11:06 pm
Pretty happy now ive got the DS1052E from Rigol with no issues at all :P
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 14, 2014, 06:14:32 pm
The 100 kHz period of the jitter showing up at a delay of 5us and not at a delay of 10us could be produced by frequency modulation of the sample clock like they do with spread spectrum modulation to meet emissions requirements.  Such modulation should not be used on a sample clock unless the effect is compensated for and some frequency counters and oscilloscopes do this deliberately to avoid synchronous sampling.  Maybe Rigol used a clock module which includes that function or the PLL which generates the sampling clock is being modulated somehow.

The trigger's AC coupling is just broken.  I noticed that the trigger was shown occurring later than the point where it should have occurred which is what I would expect if AC coupling was removing high frequency content from the trigger signal.  I can duplicate that sort of display on an analog oscilloscope or my DSOs which use analog triggering by using high frequency reject for the trigger coupling if the waveform has high frequency content to be filtered.

Would be interesting to compare results with internal vs. external function gen - something like leakage of an internal clock to the analogue trigger circuitry would probably have a different effect depending on whether or not it was synced to the scope's clock.

The triggering is digitally done after digitization so there is nothing for an external signal to affect.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: HexfeT on November 14, 2014, 06:21:24 pm
DS1054Z
Software version: 00.04.01.SP2
Board version: 0.1.1

Normal
(http://i.hizliresim.com/zE9qj7.png)

AC Coupled
(http://i.hizliresim.com/OdmOv4.png)

5us Offset
(http://i.hizliresim.com/JEmBZJ.png)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 14, 2014, 06:37:58 pm
The triggering is digitally done after digitization so there is nothing for an external signal to affect.
If that's the case it could explain the big difference in behaviour between AC & DC coupling.
As regards differences from unit to unit, that could be small differences in frequency between scope and source, i.e. it's not a unit to unit difference, it's a source to source difference.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dave3533 on November 14, 2014, 06:46:43 pm
The (trigger AC coupled) jitter on my 1054z doesn't seem to get better or worse at different horizontal offsets, but its pretty bad across the board...  :scared: lol

Software: 00.04.01.SP2
Board version: 0.1.1
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pciebiera on November 14, 2014, 06:47:28 pm
DS2072A
S/W: 00.02.01
H/W: 2.0

DC
(https://dl.dropboxusercontent.com/u/66296958/DS2000/DS2_DC.png)

AC
(https://dl.dropboxusercontent.com/u/66296958/DS2000/DS2_AC.png)

Trigger on rising and falling
(https://dl.dropboxusercontent.com/u/66296958/DS2000/DS2_SBoth.png)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: DEHiCKA on November 14, 2014, 06:47:45 pm
Major problem discovered 2 years after one of the most popular scope (DS2XXX) was released.
Apparently, nobody uses AC coupling trigger mode these days  ;)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RRobot on November 14, 2014, 07:18:46 pm
Doesn't seem to happen on my DS2072(Not A), fw 2.01, hw 2.0? Can't say I've ever used this trigger mode before either.

Edit, actually I cranked up the signal to 5 MHz and its obvious now, for those who can't see it using the calibration square wave, its probably too large a time base to see what looks to be about 8ns of jitter (on my scope).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: DeepSOIC on November 14, 2014, 07:22:13 pm
DS2102
AC trigger problem: confirmed  :-- but I've never used it!
dual-slope trigger: confirmed, but: generally works, but disappears after cycling through all trigger types. Rebooting the scope helps, as well as hitting auto button.
Software ver 00.00.01
hw ver 1.0
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jnissen on November 14, 2014, 07:36:32 pm
The 100 kHz period of the jitter showing up at a delay of 5us and not at a delay of 10us could be produced by frequency modulation of the sample clock like they do with spread spectrum modulation to meet emissions requirements.  Such modulation should not be used on a sample clock unless the effect is compensated for and some frequency counters and oscilloscopes do this deliberately to avoid synchronous sampling.  Maybe Rigol used a clock module which includes that function or the PLL which generates the sampling clock is being modulated somehow.


I've got a suspicion that is exactly what were dealing with here.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 14, 2014, 07:43:27 pm
The triggering is digitally done after digitization so there is nothing for an external signal to affect.

If that's the case it could explain the big difference in behavior between AC & DC coupling.

I think they are unrelated.  The jitter at 5us and every 10us after that looks like a problem with the sampling clock being frequency modulated at 100 kHz producing a peak to peak jitter of about 1ns on Dave's DS1054Z and about 5ns on EcProject's MSO1104Z.  The AC trigger coupling problem results in 8ns of peak to peak jitter on Dave's DS1054Z at the trigger point.

Quote
As regards differences from unit to unit, that could be small differences in frequency between scope and source, i.e. it's not a unit to unit difference, it's a source to source difference.

The jitter caused by the AC trigger coupling selection is at the trigger point so the jitter (and frequency) from the signal source is irrelevant as long as the average DC level does not change significantly and even if that was causing the problem, then the trigger point would not be offset as shown at 9:21 in Dave's video.  What is shown at that point in his video resembles what happens when a high frequency reject filter is used with analog triggering but I am sure there could be a more esoteric cause with the digital trigger.

The jitter is also not what I would expect from aliasing although if you look closely at the Tektronix example at 12:21 in the video, you can see the results of what might be aliasing immediately around the trigger point.  The Tektronix sample rate is high though so more likely it is just an artifact caused by noise interacting with the trigger.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 14, 2014, 07:49:15 pm
(http://i.imgur.com/sNxgyUK.png)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alexanderhiam on November 14, 2014, 07:52:38 pm
I got my DS1104Z as soon is they were selling in the US, and it's SW version 00.02.00.SP1. The system info doesn't show a hardware version. It has the AC coupling jitter, but doesn't have the horizontal offset jitter at all. In place of that though it has a wonderful feature where it likes to reset itself at random intervals, like while I'm in the middle of looking through a large capture... it's a fun one.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: LaurenceW on November 14, 2014, 07:57:06 pm
What's the liklihood of there being a software fix/cludge for this in the future (which might rescue earlier machines), or should we wait for Rigol to fix the hardware and tehn buy?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 14, 2014, 07:57:59 pm
Would be interesting to compare results with internal vs. external function gen - something like leakage of an internal clock to the analogue trigger circuitry would probably have a different effect depending on whether or not it was synced to the scope's clock.

The triggering is digitally done after digitization so there is nothing for an external signal to affect.

David, what makes you conclude these scopes have digital triggering?  Do you mean like the R&S RTO scopes?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 14, 2014, 07:59:41 pm
Major problem discovered 2 years after one of the most popular scope (DS2XXX) was released.
Apparently, nobody uses AC coupling trigger mode these days  ;)

AC coupled triggering is useful when DC offset is used or if the vertical positioning is done before the trigger pickoff so it acts as a DC offset control; vertical positioning and offset are often combined but they do not have to be.  If DC triggering is used in these cases, then altering the vertical position or offset also alters the trigger level which is usually not the desired behavior.

For this reason oscilloscopes which have a combined position and offset control often always use AC coupling when internal triggering is used.

Oscilloscopes which support peak to peak triggering can avoid this issue even when using DC coupled triggering.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 14, 2014, 08:02:06 pm
Could the dual-slope trigger thing be just a synchronisation/number of cycles thing - does adjusting holdoff make a difference?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EE-digger on November 14, 2014, 08:11:05 pm
As far as the jitter at delay goes, it would seem like the the architecture of the acquisition and memory systems might come into question.

On my TDS784D, I can plug in any delay value and see no jitter whatsoever.  It became scary with really long delays so I turned on FM to be sure, so I could see no "jitter" at zero delay and increasing "jitter" as the delay was increased.

On the other hand, the problem could simply be incorrect indexing when mapping acquisition memory to display memory, and adding the intensity grading process on top of that.

If it is simple, how fast is Rigol at turning around solutions?  If they are as fast as they are with revising security measures, we're all set :) :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 14, 2014, 08:15:36 pm
Would be interesting to compare results with internal vs. external function gen - something like leakage of an internal clock to the analogue trigger circuitry would probably have a different effect depending on whether or not it was synced to the scope's clock.

The triggering is digitally done after digitization so there is nothing for an external signal to affect.

David, what makes you conclude these scopes have digital triggering?  Do you mean like the R&S RTO scopes?

There are a couple of reasons:


Update: I forgot to include the trigger output jitter and the excessive delay in the trigger output.  Both indicate that a digital trigger is used.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Larry Benko on November 14, 2014, 08:45:05 pm
2 month old Rigol MSO2202A scope with Firmware 00.03.00.SP1 and Hardware 2.2.  I can NOT rerpeat either the 5 us. or AC jitter Dave saw.  Waveforms are all stable.  Current firmware is 00.03.01 which I have not loaded.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xs4hkr on November 14, 2014, 09:05:22 pm
The 5 us delay problem doesn't occur on a 1 week old MSO2072A (factory calibration date: 29-07-2014, firmware version: 00.03.00.SP1, hw version: 2.2). The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Chipguy on November 14, 2014, 09:10:48 pm
I can NOT confirm any of that on my MSO1104Z-S. Maybe I did it wrong?
My short video is here: http://youtu.be/wYKInWNtzeY (http://youtu.be/wYKInWNtzeY)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xs4hkr on November 14, 2014, 09:15:37 pm
Chipguy: you should change the coupling (to ac) in the trigger settings.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Kevman on November 14, 2014, 09:18:41 pm
I've been thinking about getting one of these to complement my CRO, if only "because..."

I'm having trouble grasping how big of a deal this is, though. Can someone give a use case for AC coupled trigger?

I didn't think my 2245A had AC trigger coupling till I just looked at it (it has AC, DC and 3 different 'noise rejects') I always just figured it followed the coupling setting for the channel...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 14, 2014, 09:19:56 pm
Did you look at the trigger-out?

No, barely had time to shoot and upload this video last night.
Going walkabout  today.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Chipguy on November 14, 2014, 09:29:08 pm
Chipguy: you should change the coupling (to ac) in the trigger settings.

Ah yeah right.
I just did that, same result. No jitter at all.
Not even worth to shoot another video.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 14, 2014, 09:35:21 pm
The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.

That is interesting!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Chipguy on November 14, 2014, 09:47:34 pm
It was a bit of work to find the right setting, but now at 20 MHz I can confirm the AC trigger jitter.
It is pretty big, awful.
Sinewaves at 1 MHz do not show any jitter, but square waves do.
It's not depening much on the amplitude. Almost the same at 100mVpp and 1Vpp.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: egonotto on November 14, 2014, 10:01:51 pm
Hi,


the AC-trigger problem is a delay between 45ns to 55ns. You can say a delay of 50ns with jitter 10ns p-p.

Therefore you need the right input to see this.

The builtin 1KHz has to large risetime.

Best Regards
egonotto
 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pciebiera on November 14, 2014, 10:03:37 pm
Another odd thing I just noticed.
When you hit run/stop it just freezes the frame buffer, but then then if you move around the waveform it updates.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 14, 2014, 10:05:52 pm
The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.

Oddly enough the old Tektronix 2465 series analog oscilloscopes do something like this in reverse with their calibration output signal.  When viewed on the oscilloscope, it will be jitter free but it is synchronized with the sweep so when viewed on a different oscilloscope or instrument, it will show significant jitter.  From their manual:

Due to internal circuitry constraints, the calibrator signal is not synchronized during trace holdoff.  This does not affect the accuracy of the calibrator signal that is present during a trace display.  However, if the calibrator signal is used to calibrate other instruments, the sweep must be shut off.  If it is not, the signal will appear to jitter and will give false (low) frequency counts.  The sweep is easily shut off by setting the trigger mode switch to single sequence.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 14, 2014, 10:13:29 pm
The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.

That is interesting!
again, suggestive of the issue relating to slight differences in frequency when using an external source that's independent of the scope's own clock
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 14, 2014, 10:23:35 pm
Has anyone tested this with a good old fashion analog  ~20 Mhz sig gen ? 

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 14, 2014, 10:27:12 pm
While I was trying the trigger issue on my DS2072, i noticed another bug.

With DC-Coupling there is a trigger-level marker, with AC-Coupling the trigge-level marker dissapears.
So it's more difficult to set the trigger correct.

This is correct behaviour, it makes absolutely no sense to draw a line on the screen when the trigger coupling is set to AC; the filtered waveform used for triggering isn't shown on the screen, so what would you be cross-referencing the line to? It's actually very good that they hide the line, shows that they've thought about it. (If only they tested it :) )
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Dave Turner on November 14, 2014, 10:28:30 pm
DS1074Z-S November 2013
SW 00.02.00.SP1
Board rev unknown.

Reset scope to default.

Using internal signal-generator source 1 at 15MHz square wave, 1v amplitude, high impedance, direct BNC-BNC connection to Ch2.

Run auto setup and select rising edge. (An oddity with my scope is that if a signal is present on Ch1 then Ch4 is also detected, hence use of Ch2. Anyone else found this?)

Trace looks fine.

a) Select trigger menu - coupling - AC and jitter is BX-AX approx 8.2ns.

b) Rerun Auto setup. Change Horizontal scale to 1us, change horizontal position to 5us, change Horizontal scale back to 5ns (as set by auto setup and rising edge).

No difference in trace.

Assuming I've tested correctly - with my scope I can verify the AC jitter but not the 5us issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Carrington on November 14, 2014, 10:29:03 pm
The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.

That is interesting!

Yes it is!

Probably there are a big difference in the rise time.

Someone else can replicate it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 14, 2014, 10:36:12 pm
I've confirmed this issue with my DS2000A series.   5 Mhz signal,  AC coupled trigger,   lot's of jitter.  Interesting that the LF Reject option significantly reduces it.   Perhaps it's picking up some internal clock.   IDK,   I doubt it's a software fix,  unless perhaps FPGA upgrade. 

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Carrington on November 14, 2014, 10:37:39 pm
Also if I remember correctly, I have read somewhere in the forum that the DS4000 series uses analog trigger instead digital.
Can anyone confirm this?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TheGreatGooglyMoogly on November 14, 2014, 10:40:24 pm
My late $0.02:

The brand new DS2302A we have in the lab here seems just fine in both AC and DC modes.
I measured a 74.25 MHz and a 54 MHz clock on an FPGA board, using AC and DC triggering and 0/5 us delay.

This was a scary video since yesterday we had a major jitter issue with a 27 MHz clock output of a video decoder chip. Turns out the clock is jittery not the 'scope!


PS... what's a 'walkabout' ?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 14, 2014, 10:42:51 pm
I'm going to go out on a limb here and say it's either picking up the LCD display back light freq or the switch mode power supply.  Most likely the display. 

The LF Reject option significantly reduces it,  but doesn't remove it.   

What can I say,  I like limbs.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 14, 2014, 10:48:22 pm
Has anyone tested this with a good old fashion analog  ~20 Mhz sig gen ? 

Yes, I get the same result on my 4000 series with a 20Mhz OCXO.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 14, 2014, 10:52:10 pm
Does bandwidth limiting to 20MHz make a difference?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 14, 2014, 10:55:22 pm
Does bandwidth limiting to 20MHz make a difference?

Nope, not on mine, delay jitter anyhow.  (I don't see the AC/DC trigger coupling issue on the 4000)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xs4hkr on November 14, 2014, 11:16:46 pm
The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.

That is interesting!

Yes it is!

Probably there are a big difference in the rise time.

Someone else can replicate it.

Yes, there is. The probe compensation signal output has an avg. rise time of 2.8 us, the signal of the generator has an avg rise time of 19.4 ns. See attachments.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Rory on November 14, 2014, 11:31:30 pm
Wondering if jitter occurs with external trigger...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Marco on November 14, 2014, 11:36:38 pm
Maybe they use analogue triggering after all and their circuits are just really crappy? I guess it might be a little cheaper, digital triggering will take a little extra space on the FPGA for wirespeed processing and FIFO/circular buffer.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wn1fju on November 14, 2014, 11:37:43 pm
My 1104Z exhibits both the 5us and AC trigger jitter.  However, I just tried the same experiment on an mid 1990's HP 83475B scope (the same as an HP 54610B with the addition of an optical sensor).  And I got the same jitter problem on the HP scope, namely if I move the horizontal delay, the waveform (in this case a 20 MHz square wave) exhibits jitter.  See the photos.  Since my methodology was to 1) get a stable trace at 5 ns/div, 2) crank the time base way up so I don't have to keep turning the delay knob forever, 3) set the delay, 4) crank the time base back down to 5 ns/div, perhaps the problem is that the acquisition rate changes when the time base is set slower and at that point, the delay is somehow geared to that acquisition, so that when I go back down, things are upset.  Of course, the HP 54610B does everything the old way through repetitive sampling to build up the waveform.  Just a thought.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 14, 2014, 11:47:42 pm
In seeking more information about this issue, I read this App-note by Agilent that talks about ADC interleaving and the effect of inaccurate phase alignment and vertical calibration of a scopes input data acquisition circuits.
http://cp.literature.agilent.com/litweb/pdf/5989-5732EN.pdf (http://cp.literature.agilent.com/litweb/pdf/5989-5732EN.pdf)

I am not sufficiently expert to advance the discussion but I did want to post this link so that someone who has read this App-note or is prepared to read it can comment on whether it may be related. It does have some testing suggestions for those with suitable equipment to perform.

Naturally it shows Agilent scopes performing closer to the ideal and doesn't mention Rigol at all.

It is an interesting document in its own right anyway, even if it proves to be off topic for this thread.

Aliasing is a real problem but does not explain why the Rigols display large amounts of jitter with AC coupling of the trigger and low amounts 5us and every 10us after the trigger.

Wondering if jitter occurs with external trigger...

Do you mean the external trigger output?

The DS1054Z series has no external trigger inputs (4 channel oscilloscopes usually do not) and the DS2000A series has one.  I have never seen an evaluation of the DS2000A external trigger input but the documentation says that some trigger modes only work with the vertical input channels and not the external trigger input.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Rory on November 14, 2014, 11:49:47 pm
In seeking more information about this issue, I read this App-note by Agilent that talks about ADC interleaving and the effect of inaccurate phase alignment and vertical calibration of a scopes input data acquisition circuits.
http://cp.literature.agilent.com/litweb/pdf/5989-5732EN.pdf (http://cp.literature.agilent.com/litweb/pdf/5989-5732EN.pdf)

I am not sufficiently expert to advance the discussion but I did want to post this link so that someone who has read this App-note or is prepared to read it can comment on whether it may be related. It does have some testing suggestions for those with suitable equipment to perform.

Naturally it shows Agilent scopes performing closer to the ideal and doesn't mention Rigol at all.

It is an interesting document in its own right anyway, even if it proves to be off topic for this thread.

Aliasing is a real problem but does not explain why the Rigols display large amounts of jitter with AC coupling of the trigger and low amounts 5us and every 10us after the trigger.

Wondering if jitter occurs with external trigger...

Do you mean the external trigger output?

The DS1054Z series has no external trigger inputs (4 channel oscilloscopes usually do not) and the DS2000A series has one.  I have never seen an evaluation of the DS2000A external trigger input but the documentation says that some trigger modes only work with the vertical input channels and not the external trigger input.

Yes I was referring to the DS2000 series external trigger input. But as a second thought, I don't recall if there is an AC coupling selection for that input in the triggering menu.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 14, 2014, 11:51:31 pm
When will someone crack open theirs and try to find the same frequendy mod on the front end?  >:D
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Carrington on November 15, 2014, 12:06:38 am
The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.

That is interesting!

Yes it is!

Probably there are a big difference in the rise time.

Someone else can replicate it.

Yes, there is. The probe compensation signal output has an avg. rise time of 2.8 us, the signal of the generator has an avg rise time of 19.4 ns. See attachments.

When you checked the AC jitter using the probe compensation output, what timebase did you use, between 2 and 10 ns or 2us?

Because evidently at 2us you can't appreciate it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 15, 2014, 12:17:21 am
Oh Dave, IMHO perhaps you should have been very explicit that you were talking about AC *trigger* coupling, not AC *signal* coupling. I can't tell what proportion of people, especially in the YouTube comments, actually understand the distinction (I sure didn't know AC trigger coupling even existed until watching this video; I'm struggling to contrive applications for it), and I see at least a few people who quite clearly don't and think that AC coupling is broken. Then again, if you were to be completely clear about every little thing, your videos would be 24 hours long, so I do understand that this is a tricky balance.

Also, more importantly:

The issue with the clock signal not generating the eye diagram you expected is not a bug -- the holdoff is a user-defined value; if that value is such that the next edge after a rising edge + holdoff delay is another rising edge, then you'll lock onto those rising edges and get rising edges all day long. A randomly chosen holdoff value has a 50/50 chance of either A) finding alternating rising/falling edges (good eye diagram), or B) finding only one or the other forever (apparently "ignoring" your request to detect both edges). By modifying the holdoff value on my DS2202, I can easily transition from A, to B (holdoff half a period longer), to A (holdoff a full period longer), to B, etc etc -- exactly as you would expect. I'd expect even analog scopes (do they have a holdoff knob?) to behave the same way; if they don't, that needs explaining. Generating eye diagrams on actually interesting data signals works fine on my DS2202 more-or-less regardless of holdoff value since the random data randomizes which edge is found next. I haven't explained myself to well, but hopefully y'all can see what I mean -- in short, that particular "issue" is totally not a bug at all, it's doing precisely what you asked for.

EDIT: To be clear, I'm not exactly defending Rigol, my opinion is:
-- Oscilloscope "ignores" request to trigger on both rising and falling edge: Not a bug at all
-- AC trigger coupling issue: Really weird bug that needs to be fixed, but the impact is miniscule compared to what it would be if AC signal coupling was broken.
-- The 5us thing: Bad bug that needs to be fixed.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: lewis on November 15, 2014, 12:19:34 am
Shite.... buy an Agilent.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 12:26:05 am
And I got the same jitter problem on the HP scope, namely if I move the horizontal delay, the waveform (in this case a 20 MHz square wave) exhibits jitter.  See the photos.  Since my methodology was to 1) get a stable trace at 5 ns/div, 2) crank the time base way up so I don't have to keep turning the delay knob forever, 3) set the delay, 4) crank the time base back down to 5 ns/div, perhaps the problem is that the acquisition rate changes when the time base is set slower and at that point, the delay is somehow geared to that acquisition, so that when I go back down, things are upset.  Of course, the HP 54610B does everything the old way through repetitive sampling to build up the waveform.  Just a thought.

The jitter of the source and the sample clock add when using a delayed acquisition and whichever is worse will limit timing accuracy.  The displayed behavior of the Rigol when used with a source which has low jitter as measured on other oscilloscopes is odd because the jitter is significant and maximum with 5us of delay and repeats every 10us after that while the jitter at 10us and every 10us after that only appears to be that of the source and trigger.

When I run this test on my 2440, jitter is about equal to the level expected from just the trigger noise out to 10us and beyond.  It actually measured just under 200ps at the trigger and just over 200ps at the delay point which matches the specifications and there was too small a difference to say whether the oscilloscope timebase or the source had more long term jitter.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xs4hkr on November 15, 2014, 12:29:54 am
The AC coupled trigger jitter problem doesn't occur when using probe compensation signal output but does occur when using an equal signal (square, 1 kHz, 3 Vpp) generated  with a function generator.

That is interesting!

Yes it is!

Probably there are a big difference in the rise time.

Someone else can replicate it.

Yes, there is. The probe compensation signal output has an avg. rise time of 2.8 us, the signal of the generator has an avg rise time of 19.4 ns. See attachments.

When you checked the AC jitter using the probe compensation output, what timebase did you use, between 2 and 10 ns or 2us?

Because evidently at 2us you can't appreciate it.

Good point. 2 us (compensation signal) and 10 ns (generator signal). But with the slower rise time that's the only way to get a reasonable representation of the signal.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 12:30:47 am
I'd expect even analog scopes (do they have a holdoff knob?) to behave the same way; if they don't, that needs explaining.

Most analog oscilloscopes support trigger holdoff or at least most of mine do.  It is hardly a rare feature if only because it is so easy to add.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TheGreatGooglyMoogly on November 15, 2014, 12:32:32 am
Oh Dave, IMHO perhaps you should have been very explicit that you were talking about AC *trigger* coupling, not AC *signal* coupling. I can't tell what proportion of people, especially in the YouTube comments, actually understand the distinction (I sure didn't know AC trigger coupling even existed until watching this video; I'm struggling to contrive applications for it), and I see at least a few people who quite clearly don't and think that AC coupling is broken. Then again, if you were to be completely clear about every little thing, your videos would be 24 hours long, so I do understand that this is a tricky balance.

HOLD THE CARRIAGE

I missed the AC trigger coupling. On the DS2302A, AC coupling causes the same jitter as seen in the video here. DC/AC input coupling don't seem to affect it. LF reject improves it, but not enough.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: staze on November 15, 2014, 12:35:41 am
AC vs DC triggering... since this seems to largely be a square wave issue, could the trigger be triggering off harmonics (randomly), and that's the cause of the jitter?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Carrington on November 15, 2014, 12:37:28 am
Good point. 2 us (compensation signal) and 10 ns (generator signal). But with the slower rise time that's the only way to get a reasonable representation of the signal.
:palm:
Obviously, but we want see if there are any jitter, however with a rise time of 2.8us at a time base of 10ns, complicated...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 12:49:38 am
I can't tell what proportion of people, especially in the YouTube comments, actually understand the distinction (I sure didn't know AC trigger coupling even existed until watching this video; I'm struggling to contrive applications for it), and I see at least a few people who quite clearly don't and think that AC coupling is broken.

For oscilloscopes which support adding a DC offset to the input signal (*) or apply the positioning signal before the trigger pickoff point, AC trigger coupling is used to prevent the trigger level from changing when the vertical offset or position is changed which is annoying.  On some of my analog oscilloscopes, AC trigger coupling is the default and DC trigger coupling is the exception because of this.

This should not be a problem with the Rigols because as far as I know, they do not have a DC offset fuction.  The AC trigger coupling might have just been a checklist feature although it is useful on oscilloscopes which do not support peak-to-peak triggering because you can set the trigger level once and leave it.

(*) A differential comparator input like a 7A13 can add huge amounts of DC offset so for instance ripple can be measured on a 100 volt input using a sensitivity of 10mV/div.  Oscilloscopes which support DC offset are usually not that extreme.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 01:00:32 am
AC vs DC triggering... since this seems to largely be a square wave issue, could the trigger be triggering off harmonics (randomly), and that's the cause of the jitter?

I have seen this happen before with oscilloscope triggers but the harmonics are synchronous with the square wave so this would not by itself explain the jitter.  When it happens, the trigger occurs after or sometimes before the fundamental of the square wave but is relatively stable.  It usually indicates a problem with the trigger circuits.

A test I would try on the Rigol is to see if the jitter when AC trigger coupling is used changes when more than one channel is active lowering the sample rate from 1 GS/s to 500MS/s or 250MS/s.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: eV1Te on November 15, 2014, 01:21:18 am
I have not been able to read all the other posts in this thread, but here are the results from my DS1074Z-S with all options unlocked and the latest firmware from Rigol (04.01.02).

No Jitter on DC with any offset.

But lots of Jitter with AC coupled trigger.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alank2 on November 15, 2014, 01:25:38 am
On my ds4k when I start with a 0-5V 20MHz square wave I hit the 50% button and put the trigger line in the center.  When switching to AC triggering that line will now be at the top of the waveform if it is being looked at from an AC point of view even though it is still displayed as DC.  If I adjust the trigger level to 0V it cleans up perfectly.  Could you guys have a trigger level issue on the AC trigger jitter?  Oddly in AC triggering and LF Reject triggering do NOT show a trigger line when adjusting - perhaps this is their way of telling you that the line being visible wouldn't correlate to the on screen waveform.  FOR THOSE OF YOU WITH THE AC TRIGGER JITTER ISSUE, IF YOU CHANGE THE THRESHOLD TO 0V, does it clean up?

Also, on the horizontal jitter issue, my ds4k doesn't get bad then clear up at 5us, 10us, etc., it just has some jitter in it anytime the trigger point is OFF of the display.  You can push the T to the left and while it is still not at the edge, it is rock solid, but push it off a little bit and it adds a slight bit of jitter.  Could it be an issue with the intensity grading code causing this?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: softwarejedimaster on November 15, 2014, 01:31:41 am
my first post is a bad one! I have the same issue with DS1054Z with jitter on a 15 Mhz sine input, only my jitter starts as early as one micro second and gets progressively worse up to 5 then disappears at 10 etc... - also same problem with AC coupling -  :wtf: Rigol!!!:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 02:58:38 am
So on the trigger AC coupling, what does it mean that it forbids DC signals into the trigger path?

No Jitter on DC coupled triggering on DS2202.

Next, feeding it a 12 MHz square wave (sorry for the bad ground probing) I surely get jitter with triggering set to AC coupling, I've never used it before, not even sure what is supposed to do.

If I change the trigger level to the peak to 2.5 Volts so it triggers on that overshoot due to bad ground probing, it jitters way less.

If I adjust the Acquisition Mem Depth to 56MPoints it dances around the jitter but only showing one wave.

If I change the Acquisition mode to Average, I can get it to clear setting it to 16 but the trigger offset (rising edge) is off (yeah I could change it with CH1 Delay-cal and make it look ok, but I'm not sure in AC coupled trigger where is supposed to trigger at if I have it set to rising edge..

I'm on an old version as well, Software: 00.01.01.00.02 Hardware: 1.0.2.0.0 etc (attached version screenshot)

I'll watch the video to see if I get an insight on what the AC coupled trigger is supposed to be used for :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: LoyalServant on November 15, 2014, 03:03:06 am
I guess I will throw my hat into the ring and say me too.
My DS2072A is quite horrible, and with a sine wave....

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: selkathguy on November 15, 2014, 03:05:54 am
Throwing my two cents in, just tested it on my DS1074Z after seeing this video.  Signal source is a Rigol DG1032Z.  No jitter problems from what I can see.  I tried to match your conditions the best I could (with the exception of amplitude).  Perhaps different firmware?  I can't imagine the front-end for the two scopes is any different, so it might be some clocking issue.

(http://puu.sh/cRdRB/623ffa5ef7.png)

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nixfu on November 15, 2014, 03:23:33 am
Ok... as stated above.

So, from what I gather this is strictly to do with using the AC TRIGGERING feature, where the jitter is occurring, not just from using normal everyday AC coupling of the input.

AC coupling, I personally do lots of times with audio signals/RF signals etc..but I don't think I have ever used any AC triggering settings yet. 


THIS IS IMPORTANT.  I do think maybe people are thinking a regularly used feature such as AC input coupling is not working property. 

If this is not the case, and I think we should make sure we don't get people into a tizzy unnecessarily.


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 03:31:41 am
but I'm not sure in AC coupled trigger where is supposed to trigger at if I have it set to rising edge.

If the trigger level when DC coupled is midway between the positive and negative peak of a waveform which has a 50% duty cycle like a square, sine, or triangle wave, then the trigger position should not change with an AC coupled trigger.  There should always be some level of AC coupled trigger which produces the same results as a DC coupled trigger.

Not only is the displayed jitter not suppose to be there but the trigger position is wrong as well.  It should be on the fast edge just like when a DC coupled trigger is used.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 03:48:00 am
As for the 5 us jitter my old version on the DS2202 has it, I don't even need to go to 5us just 1us makes it jitter and it doesn't recover at 10us nor ever.
Both test with DC trigger coupling and either DC or AC channel coupling. I guess I will have to upgrade because on Software: 00.01.01.00.02 Hardware: 1.0.2.0.0  it's horrible on my scope.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: selkathguy on November 15, 2014, 03:51:55 am
this is strictly to do with using the AC TRIGGERING feature, where the jitter is occurring, not just from using normal everyday AC coupling of the input.

AH yes,  just tested that.  Yup.  Forgive me I admit I did not read all of the posts beforehand.  From how Dave was going on in the video, I thought it was a huge input coupling jitter problem.  I've been using mine for a while, and I've never used AC triggering before.  I'm trying to wrap my head around what exactly AC triggering actually does and how it differs from the other options.  Hmm, to google!

(http://puu.sh/cRgnU/b8f00fa4af.png)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 15, 2014, 04:09:16 am
Ok... as stated above.

So, from what I gather this is strictly to do with using the AC TRIGGERING feature, where the jitter is occurring, not just from using normal everyday AC coupling of the input.

AC coupling, I personally do lots of times with audio signals/RF signals etc..but I don't think I have ever used any AC triggering settings yet. 


THIS IS IMPORTANT.  I do think maybe people are thinking a regularly used feature such as AC input coupling is not working property. 

If this is not the case, and I think we should make sure we don't get people into a tizzy unnecessarily.

correct, only ac triggering throws it off.

on 1054 i saw this:
don't see the 5ms(i used few khz signals, so it's not 5us) jitter on the built-in signal generator (1khz?), but i do see it on a bit higher freq. square wave with A HECK OF A LOT FASTER RISE TIME, in that case i see it well, it's slowly moving the waveform left/right in that jittery way....

like so:
rigLoL MVI 7418 (https://www.youtube.com/watch?v=xXw1Ira9Z68#)

trigger ac coupling issue i don't see, but probably because i tried with just positive-pulses square waves...

i think both issues were not reported earlier because they're not used that much...

when would one need those 2 anyway?
i mean if mikeselectric never used ac trigger somehow i doubt i'll develop the need to use it tomorrow, and for moving the trigger left/right....didn't really used that either...i quite like it centered....

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 04:16:37 am
Well on the old version of the DS2202
Software: 00.01.01.00.02
Hardware: 1.0.2.0.0

DC coupled trigger 5 us jitter is present, but so it's at 1 us horizontal positioning.
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=118638;image)

So I changed it to a lower frequency clock driven by an mcu around 33KHz 0 horizontal offset.
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=118640;image)

And just changing the horizontal positioning by 3 ms, it's jittery time
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=118642;image)

I think others are not seeing this on DC coupled trigger mode, so if they did fix it in the DS2000 series and I'm getting it because of my ancient update version then probably they can fix it in the DS1000Z series.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 15, 2014, 05:07:05 am
On my ds4k when I start with a 0-5V 20MHz square wave I hit the 50% button and put the trigger line in the center.  When switching to AC triggering that line will now be at the top of the waveform if it is being looked at from an AC point of view even though it is still displayed as DC.  If I adjust the trigger level to 0V it cleans up perfectly.  Could you guys have a trigger level issue on the AC trigger jitter?  Oddly in AC triggering and LF Reject triggering do NOT show a trigger line when adjusting - perhaps this is their way of telling you that the line being visible wouldn't correlate to the on screen waveform.  FOR THOSE OF YOU WITH THE AC TRIGGER JITTER ISSUE, IF YOU CHANGE THE THRESHOLD TO 0V, does it clean up?
Did not help one bit for my DS1kZ as i was already feeding it a signal with zero dc offset and had the trigger already set at 0v.

AC vs DC triggering... since this seems to largely be a square wave issue, could the trigger be triggering off harmonics (randomly), and that's the cause of the jitter?
Unlikely to be an issue unless the AC trigger circuit has a serious bandwidth limitation and the trigger point is set to something other than 0.

On my DS1k it occurs equally as bad with sine, square or triangle signals, which indicates that it is not dependent on the slope of the rising edge or the frequency domain content.

At this stage, i think people are on the right track with the cause being a spread spectrum internal clock. The fact that it doesn't happen when people use the 'S' models internal sig gen as a source is pretty solid proof.

Throwing my two cents in, just tested it on my DS1074Z after seeing this video.  Signal source is a Rigol DG1032Z.  No jitter problems from what I can see.  I tried to match your conditions the best I could (with the exception of amplitude).  Perhaps different firmware?  I can't imagine the front-end for the two scopes is any different, so it might be some clocking issue.

(http://puu.sh/cRdRB/623ffa5ef7.png)
Trigger offset should be 5us instead of 5ns
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 05:41:06 am
Can someone please explain when do we need to prevent DC signals from triggering?

Also when would you use that feature when you need AC triggering?

Thanks.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 15, 2014, 05:48:04 am
Can someone please explain when do we need to prevent DC signals from triggering?

Also when would you use that feature when you need AC triggering?

Thanks.

Your first question doesn't make any sense to me, and I asked the second a while back -- David gave a good answer (although it's not really a situation where you would use it, it's more a "this seems like a historical artefact"):

For oscilloscopes which support adding a DC offset to the input signal (*) or apply the positioning signal before the trigger pickoff point, AC trigger coupling is used to prevent the trigger level from changing when the vertical offset or position is changed which is annoying.  On some of my analog oscilloscopes, AC trigger coupling is the default and DC trigger coupling is the exception because of this.

This should not be a problem with the Rigols because as far as I know, they do not have a DC offset fuction.  The AC trigger coupling might have just been a checklist feature although it is useful on oscilloscopes which do not support peak-to-peak triggering because you can set the trigger level once and leave it.

(*) A differential comparator input like a 7A13 can add huge amounts of DC offset so for instance ripple can be measured on a 100 volt input using a sensitivity of 10mV/div.  Oscilloscopes which support DC offset are usually not that extreme.

However, I could make up some contrived situation where you have some small clock signal overlaid on a slowly varying ("DC" as far as the AC triggering coupling cap is concerned) signal. If you want to see both together on the screen, but trigger on that clock signal, then AC triggering would be useful and you'd be annoyed if you had a DSxxxx right now. Could still work around the problem by sending the signal to both channels and AC coupling one of them, and triggering of that channel.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 05:51:31 am
Ok... as stated above.

So, from what I gather this is strictly to do with using the AC TRIGGERING feature, where the jitter is occurring, not just from using normal everyday AC coupling of the input.

AC coupling, I personally do lots of times with audio signals/RF signals etc..but I don't think I have ever used any AC triggering settings yet.

correct, only ac triggering throws it off.

i think both issues were not reported earlier because they're not used that much...

when would one need those 2 anyway?
i mean if mikeselectric never used ac trigger somehow i doubt i'll develop the need to use it tomorrow, and for moving the trigger left/right....didn't really used that either...i quite like it centered....

I had to double check but the DSOs that I use the most, a 2230 and 2232, do not even have AC coupled triggering and I have never missed it but they have peak-to-peak automatic triggering which is practically the same thing.  All of my other DSOs and analog oscilloscopes have it though and my 7000 series mainframes would be more difficult to use without it.

Unlikely to be an issue unless the AC trigger circuit has a serious bandwidth limitation and the trigger point is set to something other than 0.

On my DS1k it occurs equally as bad with sine, square or triangle signals, which indicates that it is not dependent on the slope of the rising edge or the frequency domain content.

At this stage, i think people are on the right track with the cause being a spread spectrum internal clock. The fact that it doesn't happen when people use the 'S' models internal sig gen as a source is pretty solid proof.

There are two different problems Dave identified in his video.  One is the AC coupled triggering issue which I doubt is related to frequency modulation of the sampling clock if that is what is happening.  The other is the jitter which appears between the trigger point and 5us later but not 10us later which spread spectrum clocking could cause.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 05:57:55 am
Thanks rs20,

The first question was the same as the 2nd, the built in help system refers to the AC trigger coupling as in ignoring the DC component, probably referring to the DC offset Dave mentioned.

It does make sense now.

So if the clock or AC signal was offset by a varying DC signal, how will the Channel AC coupling deal with that, I guess with some math function averaging of the dc signal subtracted from the signal would come up with the same result, but math being so slow, might not be practical?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 06:12:38 am
For oscilloscopes which support adding a DC offset to the input signal (*) or apply the positioning signal before the trigger pickoff point, AC trigger coupling is used to prevent the trigger level from changing when the vertical offset or position is changed which is annoying.  On some of my analog oscilloscopes, AC trigger coupling is the default and DC trigger coupling is the exception because of this.

This should not be a problem with the Rigols because as far as I know, they do not have a DC offset fuction.  The AC trigger coupling might have just been a checklist feature although it is useful on oscilloscopes which do not support peak-to-peak triggering because you can set the trigger level once and leave it.

However, I could make up some contrived situation where you have some small clock signal overlaid on a slowly varying ("DC" as far as the AC triggering coupling cap is concerned) signal. If you want to see both together on the screen, but trigger on that clock signal, then AC triggering would be useful and you'd be annoyed if you had a DSxxxx right now. Could still work around the problem by sending the signal to both channels and AC coupling one of them, and triggering of that channel.

I know of one place where AC coupled triggering comes in very handy.  If your oscilloscope does not support peak-to-peak auto triggering (*) and you are probing different logic levels and want the ground reference to remain fixed so you can see the actual DC levels, then you can set the trigger coupling to AC and the trigger level close to zero and no matter where you probe, the oscilloscope will trigger correctly without adjusting the trigger level.  In this case it acts as a poor version of peak-to-peak triggering.  I use it when dealing with mixed families of logic and mixed signal circuits.

(*) The last oscilloscopes that I know of which supported peak-to-peak automatic triggering are the Tektronix 22xx series analog and DSO models from 1994 and they do not even have AC trigger coupling because it would be superfluous.  Their successors support auto level where if there is no trigger within a timeout period, the trigger level is reset to the midpoint between the signal peaks but this is much slower and they do support AC coupled triggering.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 15, 2014, 06:25:01 am
So if the clock or AC signal was offset by a varying DC signal, how will the Channel AC coupling deal with that, I guess with some math function averaging of the dc signal subtracted from the signal would come up with the same result, but math being so slow, might not be practical?

Channel 1/2 AC coupling (as opposed to AC trigger coupling) is achieved using a real-life DC blocking cap in the input stage. So that works just fine; if you want to view only the AC component of a wave, you enable Channel 1/2 AC coupling, and (perhaps confusingly) leave the trigger coupling on "DC" (i.e., a normal, non-DC-blocking connection to the already AC-coupled input signal). That way you see only the AC component on the screen, and you can move the trigger level up and down on the screen and it behaves exactly as you always expected.

Basically, just pretend the AC trigger coupling option doesn't even exist, because I'd guess that half the people on this forum didn't even know the option existed before today (myself included); turns out it's broken anyhoo, so just don't touch it. "DC trigger coupling" is what you've always known and does exactly what you've always needed.

I know of one place where AC coupled triggering comes in very handy.  If your oscilloscope does not support peak-to-peak auto triggering (*) and you are probing different logic levels and want the ground reference to remain fixed so you can see the actual DC levels, then you can set the trigger coupling to AC and the trigger level close to zero and no matter where you probe, the oscilloscope will trigger correctly without adjusting the trigger level.  In this case it acts as a poor version of peak-to-peak triggering.  I use it when dealing with mixed families of logic and mixed signal circuits.

This is a very good and genuinely useful idea -- for the first time, now I'm slightly disappointed that the feature is broken on my DS2202. Hopefully it can be fixed. Nevertheless, this still feels like a fairly specialized broken feature, rather than a flaw with the core, everyday functionality.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 15, 2014, 06:43:59 am
I'm going to jump on the "It's not the end of the world" bandwagon.   Cause it's not.   For the price I paid for my 300 Mhz scope well..I just can't complain. 

Interesting testing this issue however,  I found it decrease around 14.71 - 14.97 Mhz.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RigolTechUSA on November 15, 2014, 07:28:45 am
**The attached PDF has the scope shot images included and formatted.**

Dave, as always thanks so much to you and the community for always digging deep into instruments. Everyone here always does a great job with all of their testing!

Dave did a great job of documenting 3 different issues across a number of products.
1)   5 us jitter
2)   AC trigger coupling
3)   Rising & Falling trigger
The 5 us jitter issue I have described as:
   Trigger jitter variance displayed at 5 us odd intervals of positive trigger offset. I.E. when the trigger is 5 us, 15 us, 25 us… before the center of the display some jitter appears that doesn’t appear otherwise.

We tested 3 DS1000Z scopes here with different board revisions including the FW and HW used by Dave. Screenshots of the results in the attachment.

Scope 1: shows model and revisions as well as 5 us, 15 us, and 25 us offset.

Scope 2: shows model and revisions as well as 0 us, 5 us, and 25 us offset.
   
Scope 3: shows model and revisions as well as 0 us, 5 us, and 15 us offset.
   
None of the scopes showed the problem at all.

Conclusions:
None of the scopes we have show any change in the jitter based on trigger delay as far as I can tell. All 3 units with different hardware running the latest FW were rock solid. I was actually hoping to find one that was a little off because I expect a proper warm up and self-cal may solve the issue. You can find the self-cal in the utility menu.  Anyone seeing this issue should try a self-cal and if the problem still exists please contact Rigol. If the instrument is out of spec we will absolutely help you with that. We haven’t had any report of this problem to date in the USA and a self-cal is a good first check. Certainly, if Mads from EcProjects scope doesn’t improve when properly calibrated then it is a bad unit that needs repaired, but tests here indicate that it is not systemic and may be fixed with a self-cal. Dave, can you give yours a warm-up and self-cal and let us know if you see any change at 5 us intervals?   

It is also worth noting that if this does continue in some scopes I’d expect a Firmware update solution. Most, if not all, of the DS1000Z triggering sub system is digital. It is handled by FPGAs predominantly. There is no real inherent jitter in those captured signals, so I’d expect a FW solution if there is a verified problem on some units after a self-cal.

AC trigger coupling

Definition: Setting the Edge trigger to AC coupling causes crazy trigger insanity.

We tested this on 4 different scopes (The previous 3 as well as a DS2000A). Using the scope the way Dave does I verified what he sees. That is an issue that we will immediately address. However, the reason no one has noticed it until now is that isn’t really the normal way to look at AC Coupled signals in these scopes. We look at AC coupled signals all the time for a variety of tests without issue. The best reason to do this is often to test a signal with DC offset and keep it centered on the display and not have to get knob cramp by having to always adjust channel and trigger levels as the DC offset changes. The way I do it is to go into the channel menu and set the coupling on the channel to AC and leave the trigger coupling at the default settings. Here is a good example:

The input signal is a 20 MHz square wave (unterminated, like Dave’s) except I’ve added a 5 V offset. So, this signal actually goes from 7.5 V – 2.5 V.
 
By changing to AC Coupled in the Channel menu it centers around 0 V as expected.
 
Now notice the trigger line almost right at 0 V. The trigger system is being fed the AC coupled signal from the channel allowing you to trigger with the signal as it is shown on the screen. This is the common and normal way to use AC Coupling on a channel. As you can see this works great! AC coupling just the trigger and not the channel is pretty confusing because it either does nothing if the signal is centered around 0 V or you would then have to trigger at a level close to 0 V at a different point on the display than where the signal appears. So, you could no longer set the trigger level visually. Because of that confusion I’d never use the coupling in the trigger menu and would always use the coupling in the channel. That’s not to say that it shouldn’t work, but I can’t think of any reason why I’d want to use that setting since any signal I put into it I want to have coupled AC on the display as well. So, I think there is a much better way to use the scope, but it is still something we will fast track a firmware version to improve.

Problem 3: Rising/Falling Trigger issue
Checking this on our DS2000A here I believe what Dave sees is a combination of trigger holdoff and the AC coupling issue above. When I measure on an AC coupled channel leaving the Trigger settings alone except for setting it to Rising and Falling it looks great on our scope.
 
With rising and falling you have to be careful with these repeating square waves. Especially, it turns out at 20 MHz. A 20 MHz square wave takes 50 ns and the default trigger holdoff on the DS2000 is 100 ns so you are always catching one side of the wave because of the holdoff. If you really want to catch both sides of the wave make sure your trigger holdoff doesn’t force you to repeat triggers on one side of the wave consistently.

In summary, great detective work, as always, by Dave and Rigol users worldwide! Keep using your scopes to capture all types of waves including AC coupled waves. We are allocating resources to make sure even the corner cases we have found here exceed expectations. As the instruments are clearly capable of triggering and measuring all signals within their domain whether DC coupled, AC coupled, rising and falling, or with a specified trigger offset I don’t see any hardware issues across any of the released versions. Improvement in guiding users on how to make measurements and when to use settings is and needs to be a continuous process.

I can’t think of any use cases on this scope where you would want to AC couple the triggering of a DC coupled channel. It doesn’t work for me. If anyone is willing to share insight with us please follow this link to help us improve the interface.

http://beyondmeasure.rigoltech.com/acton/form/1579/0019:d-0001/1/index.htm (http://beyondmeasure.rigoltech.com/acton/form/1579/0019:d-0001/1/index.htm)

Here is a summary of the questions after the link in case you want a sneak peak:
•   How often do you use AC coupling on your scope?
•   When you use AC coupling on a channel, why do you do it?
•   When you trigger on a AC coupled signal how often do you want to view that signal DC coupled on the display? If you do, please explain the use case.
•   If you do this, how do you want the trigger level shown on the display since it is now decoupled from the signal visualization on the display?

Lastly, if anyone has questions or concerns they want to discuss with us, we are always here. Contact your local Rigol office or distribution partner. Our USA number is 877-4-RIGOL-1. Every DS1000Z bought in the USA is under our 3 year warranty program and Rigol quality is important to us all over the world.

Thanks,

Chris Armstrong
Director of Product Marketing & SW Applications
Rigol Technologies USA
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on November 15, 2014, 08:00:20 am
Two thumbs up for RigolTechUSA takes guts to post.

What I heard:

If the product has a problem it can be fixed let us fix it, we want to keep you as a customer. 

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 08:04:01 am
Also I want to note that Dave's test where done with the channels AC coupled, not DC coupled for the 5 us tests as your pictures show.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: staze on November 15, 2014, 08:09:57 am
AC vs DC triggering... since this seems to largely be a square wave issue, could the trigger be triggering off harmonics (randomly), and that's the cause of the jitter?

I have seen this happen before with oscilloscope triggers but the harmonics are synchronous with the square wave so this would not by itself explain the jitter.  When it happens, the trigger occurs after or sometimes before the fundamental of the square wave but is relatively stable.  It usually indicates a problem with the trigger circuits.
This makes perfect sense. Thanks!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: staze on November 15, 2014, 08:17:17 am
Huge thanks for responding Rigol! Sounds like the 5us trigger bug probably got fixed in a firmware Dave isn't running (but who knows). Dave, can you show/post which firmware/hardware you're running on the 1000z and 2000 dso's? Or could be the calibration (which I've done since I've had the scope). I'm not seeing the 5ns jitter, but I certainly see the AC coupled triggering jitter. wow. But, can't say I have any use for it. =)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 08:31:07 am
Huge thanks for responding Rigol! Sounds like the 5us trigger bug probably got fixed in a firmware Dave isn't running (but who knows). Dave, can you show/post which firmware/hardware you're running on the 1000z and 2000 dso's? Or could be the calibration (which I've done since I've had the scope). I'm not seeing the 5ns jitter, but I certainly see the AC coupled triggering jitter. wow. But, can't say I have any use for it. =)

Not fixed yet, Rigol used the Channel DC coupling for those tests as shown here (in red box), Dave had the Channel AC coupled for the 5 us bug.

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=118662;image)

Edit: just watched Dave's video again and he did indeed have the channel DC coupled, so maybe it's fixed after all.

Still. Thanks for the fast response about trying to solve this issue  :clap:  :clap:  :clap:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mikeselectricstuff on November 15, 2014, 08:39:58 am

We tested 3 DS1000Z scopes here with different board revisions including the FW and HW used by Dave. Screenshots of the results in the attachment.
None of the scopes showed the problem at all.

What was the signal source?
 Did you try making small variations to the frequency?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rf-loop on November 15, 2014, 09:09:44 am

AC trigger coupling

.
.
.

I can’t think of any use cases on this scope where you would want to AC couple the triggering of a DC coupled channel. It doesn’t work for me. If anyone is willing to share insight with us please follow this link to help us improve the interface.

http://beyondmeasure.rigoltech.com/acton/form/1579/0019:d-0001/1/index.htm (http://beyondmeasure.rigoltech.com/acton/form/1579/0019:d-0001/1/index.htm)

Here is a summary of the questions after the link in case you want a sneak peak:
•   How often do you use AC coupling on your scope?
•   When you use AC coupling on a channel, why do you do it?
•   When you trigger on a AC coupled signal how often do you want to view that signal DC coupled on the display? If you do, please explain the use case.
•   If you do this, how do you want the trigger level shown on the display since it is now decoupled from the signal visualization on the display?

Lastly, if anyone has questions or concerns they want to discuss with us, we are always here. Contact your local Rigol office or distribution partner. Our USA number is 877-4-RIGOL-1. Every DS1000Z bought in the USA is under our 3 year warranty program and Rigol quality is important to us all over the world.

Thanks,

Chris Armstrong
Director of Product Marketing & SW Applications
Rigol Technologies USA

Note: I do not have any Rigol scope today but this whole question about separately set trigger coupling AC when trigger source is signal channel where is also AC/DC coupling and specially when we talk scopes what have digital side trigger generation, is common, not brand related.


•   How often do you use AC coupling on your scope?

Very often.

•   When you use AC coupling on a channel, why do you do it?

For block DC / very low f AC from signal.  One simplest example is testing power supplies ripple.
But then also I use sometimes oscilloscope  input DC coupling but external very low freq corner DC block for analyze very low freq signals but blocking still DC from signal. (some example is also example some amplifier etc 1/f noise)

•   When you trigger on a AC coupled signal how often do you want to view that signal DC coupled on the display? If you do, please explain the use case.

If your guestion is: Signal input A and input coupling DC  and  Trigger coupling AC and trigger source from this same channel A.

Answer is: Never.  (exept in some very rare cases with some old analog scope for finding trigger stability)

Specially in cases that trigger is generated digitally from digitized signal somewhere after ADC.
And if I have understood right Rigol these models have digital trigger if source is input channel.

In this case also if signal input A and input coupling AC  and Trigger coupling AC and trigger source from this same channel A.

Answer is: Never.

I can not imagine any need in this case for set trigger coupling AC in this kind of oscilloscope where trigger is derived from digitized side of main channel.  This setting in this setup combination can remove from scope menu.

In old analog scopes where trigger is analog derived from input or ext trig and also both AC/DC couplings are in separate independent pathways my answer is different but not handle it here.


•   If you do this, how do you want the trigger level shown on the display since it is now decoupled from the signal visualization on the display?

If someone do this my opinion is that he do not really understand what he is doing  and what he want. Exept if want find feature (setup) what do not need occur at all. 



Then, but this is totally different case.
If talk about EXT trig channel, this is different case. (btw, how Rigol produce trig there. Analog comp. method? I have not seen ADC there.
So or so but there this EXT trig channel input coupling need of course have also AC.)

When signal source is main channel where is selectable input AC/DC coupling, and trig is produced from main channel digitized data, there is no need for separate trigger AC/DC coupling. Who can  logically explain what useful it may do and for what it is implemented.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TheBay on November 15, 2014, 09:47:08 am

AC trigger coupling

.
.
.

I can’t think of any use cases on this scope where you would want to AC couple the triggering of a DC coupled channel. It doesn’t work for me. If anyone is willing to share insight with us please follow this link to help us improve the interface.

http://beyondmeasure.rigoltech.com/acton/form/1579/0019:d-0001/1/index.htm (http://beyondmeasure.rigoltech.com/acton/form/1579/0019:d-0001/1/index.htm)

Here is a summary of the questions after the link in case you want a sneak peak:
•   How often do you use AC coupling on your scope?
•   When you use AC coupling on a channel, why do you do it?
•   When you trigger on a AC coupled signal how often do you want to view that signal DC coupled on the display? If you do, please explain the use case.
•   If you do this, how do you want the trigger level shown on the display since it is now decoupled from the signal visualization on the display?

Lastly, if anyone has questions or concerns they want to discuss with us, we are always here. Contact your local Rigol office or distribution partner. Our USA number is 877-4-RIGOL-1. Every DS1000Z bought in the USA is under our 3 year warranty program and Rigol quality is important to us all over the world.

Thanks,

Chris Armstrong
Director of Product Marketing & SW Applications
Rigol Technologies USA

Note: I do not have any Rigol scope today but this whole question about separately set trigger coupling AC when trigger source is signal channel where is also AC/DC coupling and specially when we talk scopes what have digital side trigger generation, is common, not brand related.


•   How often do you use AC coupling on your scope?

Very often.

•   When you use AC coupling on a channel, why do you do it?

For block DC / very low f AC from signal.  One simplest example is testing power supplies ripple.
But then also I use sometimes oscilloscope  input DC coupling but external very low freq corner DC block for analyze very low freq signals but blocking still DC from signal. (some example is also example some amplifier etc 1/f noise)

•   When you trigger on a AC coupled signal how often do you want to view that signal DC coupled on the display? If you do, please explain the use case.

If your guestion is: Signal input A and input coupling DC  and  Trigger coupling AC and trigger source from this same channel A.

Answer is: Never.  (exept in some very rare cases with some old analog scope for finding trigger stability)

Specially in cases that trigger is generated digitally from digitized signal somewhere after ADC.
And if I have understood right Rigol these models have digital trigger if source is input channel.

In this case also if signal input A and input coupling AC  and Trigger coupling AC and trigger source from this same channel A.

Answer is: Never.

I can not imagine any need in this case for set trigger coupling AC in this kind of oscilloscope where trigger is derived from digitized side of main channel.  This setting in this setup combination can remove from scope menu.

In old analog scopes where trigger is analog derived from input or ext trig and also both AC/DC couplings are in separate independent pathways my answer is different but not handle it here.


•   If you do this, how do you want the trigger level shown on the display since it is now decoupled from the signal visualization on the display?

If someone do this my opinion is that he do not really understand what he is doing  and what he want. Exept if want find feature (setup) what do not need occur at all. 



Then, but this is totally different case.
If talk about EXT trig channel, this is different case. (btw, how Rigol produce trig there. Analog comp. method? I have not seen ADC there.
So or so but there this EXT trig channel input coupling need of course have also AC.)

When signal source is main channel where is selectable input AC/DC coupling, and trig is produced from main channel digitized data, there is no need for separate trigger AC/DC coupling. Who can  logically explain what useful it may do and for what it is implemented.
Very valid points. I use AC coupling for smps and audio work. But am I reading this right and from my tests AC coupling is not affected, I certainly see no issues on my DS2702. It's just AC triggering. Which I have never used on any scope?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 15, 2014, 10:17:37 am
Changing the channel coupling does not fix the 5us issue. Channel coupling is completely independent of the jitter issues. Also, my DS1054Z has firmware 04.02.SP3 which is even newer than what RigolTechUSA is running and it still suffers from the 5us problem.

Channel coupling DC, trigger coupling DC = ok at 0us, jitter at 5us.
Channel coupling AC, trigger coupling DC = ok at 0us, jitter at 5us.
Channel coupling DC, trigger coupling AC = jitter at 0us, very bad jitter at 5us.
Channel coupling AC, trigger coupling AC = jitter at 0us, very bad jitter at 5us.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: electr_peter on November 15, 2014, 10:32:36 am
Alan has made a video about trigger coupling on analog scopes (from 5:00)
Tektronix Oscilloscope Triggering controls and their usage (https://www.youtube.com/watch?v=OFGm-Pel4Hg#)

Basically, AC trigger coupling allows to keep trigger level at the same spot when signal reference level is moved up and down. I do not see how this could be used on or apply to digital scope.

 :-+ for Rigol for looking at the issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 15, 2014, 10:34:29 am
I am not at all convinced that Rigol testing 3 scope means the problem does not exist and/or has not been fixed. There are too many people have reported it, including the very last post with newer firmware than Rigol used.
So either Rigol lucked out with the 3 scope they are using (based on the reports, not all units are affected), or they have used an input signal which is not causing it. There are few reports that the signal rise time might be the issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 15, 2014, 10:35:42 am
I did not expect anyone to so badly confuse AC trigger coupling with AC input coupling. I'm pretty sure I showed I was suing the trigger menu more than once in the video, and mentioned it was trigger coupling.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: frogmaster on November 15, 2014, 10:47:48 am
There is no real inherent jitter in those captured signals, so I’d expect a FW solution if there is a verified problem on some units after a self-cal.

I performed a self-cal yesterday, makes no difference.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 15, 2014, 10:51:51 am
There is no real inherent jitter in those captured signals, so I’d expect a FW solution if there is a verified problem on some units after a self-cal.

I performed a self-cal yesterday, makes no difference.
Yep, me too. No difference.

I'm pretty convinced that it is an issue with frequency modulation of the system clock. That would go a long way to explain why no one can replicate the issue using scopes own function generator, yet there is an abundance of people who can with external generators.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: eV1Te on November 15, 2014, 11:04:18 am
I'm pretty convinced that it is an issue with frequency modulation of the system clock. That would go a long way to explain why no one can replicate the issue using scopes own function generator, yet there is an abundance of people who can with external generators.

That sounds like a logic conclusions.

However I can not reproduce the 5 us jitter with any settings (always using external signal generator, DS1074Z-S, 04.01.02). Apparently some scopes do not have the Jitter for real, and it is not only related to people using the internal signal gen.

Or is there a special settings that is needed in order to reproduce the jitter?

I still have the AC trigger jitter, that seems to be a separate issue.

Edit:
The built in signal generators outputs drifts over time with respect to each other, they seem to have different source clocks...  :wtf:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 15, 2014, 11:21:11 am
What would be interesting would be if someone can check if there is measurable jitter at 5us on a signal generated by a DS1000Z-S with another scope that is not a 1000Z.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 15, 2014, 11:41:17 am
I performed a self-cal yesterday, makes no difference.

I had also performed a self-cal some time before that (within 24 hours) as part of my review video.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 15, 2014, 11:42:42 am
Or is there a special settings that is needed in order to reproduce the jitter?

Some reports seem to indicate it is rise-time related. Mine was sub 20ns I think.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tirulerbach on November 15, 2014, 11:53:42 am
My DS2000A don't show the 5us-Jitter.

But for the AC-trigger issue I discovered it a few month ago, too. First I though that my test setup was buggy and I changed it. So I didn't bothered. Never noted the public.

But, important, there are some more bugs in the trigger system (at least DS2000A):

a.) Setting "Ext.-Trigger" with "AC-Coupling" don't work et all. The extern trigger is always DC coupled.

b.) Same with the LF- and HF-reject on extern triggering: Don't work.

c.) Using extern trigger in DC-mode cause some jitter too, but not as much as with AC-trigger on a channel.


So, maybe Rigol, if you touching the code for the AC-trigger anyway please take a look at the other issues as well. Seldom used feature, but annoying.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 15, 2014, 12:03:21 pm
Or is there a special settings that is needed in order to reproduce the jitter?

Some reports seem to indicate it is rise-time related. Mine was sub 20ns I think.
I haven't seen any solid proof that it's affected by rise time, i think people are getting confused at what they are observing.

Here is a 5MHz square wave generated by my DG4000, DC coupled everything:
(https://farm8.staticflickr.com/7556/15173991653_45bea0ae26_b.jpg)

Now here is 20MHz sine wave, without touching any of the settings on the scope
(https://farm8.staticflickr.com/7561/15173991633_32686c8128_o.png)

And here's a 5MHz sine wave, again without adjusting anything on the scope.
(https://farm8.staticflickr.com/7554/15173991643_2073b01302_b.jpg)

Obviously it looks less severe with a slower rise time because the trace isn't as fat but if you observe the amount of the x-axis that the trace covers at the zero crossing you find that the amount of jitter is exactly the same at around 8ns wide for all of the signals.

edit: now that i look back at rolycat's post (reply #17), his is really severe, over 20ns!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 15, 2014, 12:14:48 pm
I did not expect anyone to so badly confuse AC trigger coupling with AC input coupling. I'm pretty sure I showed I was using the trigger menu more than once in the video, and mentioned it was trigger coupling.

Yeah, I watched the video again and you did indeed use the "triggering" word in there quite a lot, so my earlier criticism was too harsh. I guess the issue is that people not watching with 110% attention will just hear "AC coupling", see the Coupling > AC/DC menu on the screen, and just sort of think "oh yeah, that AC coupling thing I'm familiar with". An explicit "this is NOT the thing you're thinking of" would have prevented some confusion (but again, I'm very much saying this with a huge benefit of hindsight and third-partyness.) Keep up the awesome work!

BTW, I've just got a video rendering now explaining the dual slope thing. In short, not a bug at all, just an interaction between the holdoff (in your case, the default ~100ns or so holdoff on the DS2202 vs the smaller default holdoff on the DS1000Z), and the period of the 20 MHz wave  :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: hans on November 15, 2014, 12:19:43 pm
There is no real inherent jitter in those captured signals, so I’d expect a FW solution if there is a verified problem on some units after a self-cal.

I performed a self-cal yesterday, makes no difference.
Yep, me too. No difference.

I'm pretty convinced that it is an issue with frequency modulation of the system clock. That would go a long way to explain why no one can replicate the issue using scopes own function generator, yet there is an abundance of people who can with external generators.

I have got a DS1074Z-S and I have not seen any "5us jitter" issues with a internal signal generator or an external signal source (25MHz oscillator on a PCB). The scope is an "older" model from spring this year, and I the impression I get is that most if not all issues appear on much newer batches of scopes (especially surrounding the brand-new 1054Z).
The AC coupling triggering issue is there on my older model.

Also the signal generator in the -S models are on a separate module:
https://www.flickr.com/photos/jameslothian/sets/72157645222357567/ (https://www.flickr.com/photos/jameslothian/sets/72157645222357567/)

The bottom has a 10MHz crystal mounted, with various support circuits around it probably for driving the oscillator into the FPGA. The FPGA can have PLLs to multiple it to the 200MS/s clock rate required for updating the DAC's. It's a completely time base than the scope timebase.





If I AC trigger on a square wave from the internal signal generator the trigger phase is way off (the trigger center is lagging by tens of nano seconds) and lots of jitter. If I use a sine wave and move the trigger point near the peaks the hardware frequency counter stops counting, yet the scope triggers without any or much jitter. However the update rate is rather low, so I assume it's a very marginal trigger setting. There is a band where the hardware frequency is erroneous in frequency but the update frequency is sufficient (>8k wfms, which is probably it's maximum for the time base) and there is still very little jitter.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rf-loop on November 15, 2014, 12:39:14 pm
I hope Rigol answer this question or someone who really know.

Attached is image.

Do Rigol (DS1000Z and/or DS2000) use conventional trigger principle (top in image) or true digital trigger system (bottom in image).

If trigger system is digital, then:  What is exactly trigger coupling AC doing there? How it is implemented in this case. (And for what purpose this setting is in this case)

Also overall good to read this whole appnote from R&S. (http://cdn.rohde-schwarz.com/pws/dl_downloads/dl_application/00aps_undefined/Benefits_of_RTO_digital_trigger_system_2.pdf)

So, which one in principle?  And as told, I do not wait "maybe" answers and speculations.



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 15, 2014, 12:47:10 pm
Do Rigol (DS1000Z and/or DS2000) use conventional trigger principle (top in image) or true digital trigger system (bottom in image).

If trigger system is digital, then:  What is exactly trigger coupling AC doing there? How it is implemented in this case. (And for what purpose this setting is in this case)

Rigol pretty clearly stated earlier in the thread that it's all going on in FPGAs, so the bottom image is more relevant. You can still offer (or, if you insist, "emulate") AC trigger coupling by highpass filtering the samples, and this is useful for exactly the same reasons outlined earlier in the thread (link (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg550798/#msg550798)). Whether it's done in the digital or analog domain is of little relevance to its usefulness (but fortunately, that fact that it's digital makes it more likely to be repairable).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Supercharged on November 15, 2014, 12:48:24 pm
I can't reproduce either errors on my DS1074Z-S (Software version 00.02.03.SP5), by using the internal Function generator.

Hardware versions?

Alexander.

My Scope doesn't show the hardware version for some reason.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Carrington on November 15, 2014, 01:23:28 pm
@ TMM: Thanks for checking that. Indeed, the jitter seems constant.

Anyone know what type of trigger is used in the DS4000 series (Digital or Conventional)?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 01:35:36 pm
But, important, there are some more bugs in the trigger system (at least DS2000A):

a.) Setting "Ext.-Trigger" with "AC-Coupling" don't work et all. The extern trigger is always DC coupled.

b.) Same with the LF- and HF-reject on extern triggering: Don't work.

c.) Using extern trigger in DC-mode cause some jitter too, but not as much as with AC-trigger on a channel.

I have always wondered about the last thing in your list with the 2-channel DS2000A series.  If the external trigger input uses a comparator and reference to drive one of the FPGA logic inputs, then its timing resolution should be limited to that of the FPGA's internal clock unless they implemented some sort of time delay counter.  The same thing should happen if one of the digital MSO inputs is being used for external triggering.

The resulting trigger jitter would not be random though; it should show as discrete bands.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nuno on November 15, 2014, 01:51:24 pm
Or is there a special settings that is needed in order to reproduce the jitter?

Some reports seem to indicate it is rise-time related. Mine was sub 20ns I think.

I don't see the 5us issue (signal is the same at -5us, 5us or 0us) in a (cal certificate issued 13 May 2014) DS1104Z-S (00.04.00), using the internal siggen's square wave (15MHz), which has 10ns raise/fall times (as measured by the scope). Tried hold off from 16ns to >200ns. Same results for sine wave @ 20MHz. The internal siggen only does 5Vpp; what is the amplitude of your test signal? Seems you have the channel on 10V/div but the wave takes lots of divs.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 15, 2014, 01:53:12 pm
I know there's been little to no discussion of the dual-slope triggering "bug" mentioned in the video, but I just wanted to point out that this is not a bug at all, rather an artefact caused by trigger holdoff working correctly.

So I put together a quick little video explaining how trigger holdoff causes the observed behaviour -- and I also show how holdoff (even the default, minimum setting) could cause real confusion even if you're using normal edge triggering. This is not Rigol specific, this applies to any scope (with a trigger). With the DS2202 @ factory default settings, these problems could potentially (in admittedly somewhat contrived circumstances) bite you at frequencies as low as 5 MHz.

Oscilloscope triggering holdoff trap (https://www.youtube.com/watch?v=O8zJAdu7Trs#ws)

Why do the DS1000Z and DS2202 behave differently in the EEVBlog video? Because the default(=minimum) holdoff of the DS1000Z, 16ns, is less than the 100ns of the DS2202. 16ns fits inside a 20 MHz pulse (25 ns), 100ns does not. Neither is right nor wrong, and both can be configured to behave as desired.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tom66 on November 15, 2014, 01:57:54 pm
Hmm, isn't this just a characteristic of any delayed trigger on any oscilloscope?

I had an old HP 54501A. 10MSa/s ADC. As the trigger delay increased, jitter increased. It made anything more than about 1ms completely unusable on continuous trigger mode.

This makes sense, as the distance from the trigger point increases, the jitter becomes a sum of all previous samples. At 1GSa/s, 5 microseconds is 5,000 samples. For a jitter of ~5ns, the per-sample jitter would have to be ~1ps.

To me, that sounds completely reasonable...

Does my reasoning sound right?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: siggi on November 15, 2014, 02:01:28 pm
Here's an idea.
The AC trigger jitter could come about if the averaged (DC level) of the input signal is discarded after each acquisition, as it well might be in a digitial trigger system. In this case, the DC level would be offset slightly on each acquisition, depending on how the aquisition start time "beats" against the signal being measured.

This can probably be measured and quantified by modulating the duty cycle of the signal being measured, as the frequency of the jitter ought to go down by the duty cycle - the odds of starting a capture off on the wrong foot decreases with the duty cycle. Modulating the duty cycle of a gated signal should work too, and by setting the gate frequency and/or scope holdoff, it should be possible to set up such that the jitter dissappears by providing a DC signal for the scope to measure at the start of each acquisition.

If this is in fact the issue, then the fix ought to be relatively straightforward software fix - just a matter of keeping the last aqcuisition's DC level around for the next cycle.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 15, 2014, 02:02:55 pm
Does my reasoning sound right?

Some jitter is theoretically expected, but nowhere near as bad as shown in Dave's video. Also, it's not standard jitter, because the problem is present at 5, 15, and 25 us, but not at 0, 10, 20, etc. This doesn't fit your description at all.

But more to the point, it's just the sheer amount of jitter that is completely unacceptable, and way worse the comparable scopes or what should be easily achievable.

Here's an idea.
The AC trigger jitter could come about if the averaged (DC level) of the input signal is discarded after each acquisition, as it well might be in a digitial trigger system. In this case, the DC level would be offset slightly on each acquisition, depending on how the aquisition start time "beats" against the signal being measured.

A very plausible idea. I like it  :-+
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: c4757p on November 15, 2014, 02:04:16 pm
Yes, I believe it does. This whole thing seems blown a bit out of proportion to me... Jitter is always pretty bad when you go off-trigger.

Consider: yes, it looks worse on the DS1000Z/DS2000, but these scopes also have a significantly better graded-intensity display, requiring them to capture significantly more samples and combine them into a screenful. That's naturally going to appear to amplify the jitter.

Sounds reasonable to me. :=\

Here's an idea.
The AC trigger jitter could come about if the averaged (DC level) of the input signal is discarded after each acquisition, as it well might be in a digitial trigger system. In this case, the DC level would be offset slightly on each acquisition, depending on how the aquisition start time "beats" against the signal being measured.

Though, that also sounds plausible. Hmm... the fact that the 10us period seems to remain constant at different signal frequencies might suggest that the level is being averaged over a fixed number of samples rather than a single cycle.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: kwass on November 15, 2014, 02:26:23 pm
I performed a self-cal yesterday, makes no difference.

I had also performed a self-cal some time before that (within 24 hours) as part of my review video.

I just did a self-cal on my 1054z and also found no change to the jitter problem.  The jitter also increases gradually as the delay is moved from 0 to 5us then decreases from 5us to 10us, etc..   It's linear with about 1.5ns of jitter per 1us of delay.

Firmware: 00.04.01.SP2
Board: 0.1.1



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 15, 2014, 02:35:47 pm
Major problem discovered 2 years after one of the most popular scope (DS2XXX) was released.
Apparently, nobody uses AC coupling trigger mode these days  ;)

We've been talking about problems with AC-coupling the trigger over at the DS2000 review thread for over 2 years now (check out the bug list). Few of us original owners use that setting because of this - and I've never found a single instance in my use of the DSO in that time where I needed it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: siggi on November 15, 2014, 02:36:24 pm
Here's an idea.
The AC trigger jitter could come about if the averaged (DC level) of the input signal is discarded after each acquisition, as it well might be in a digitial trigger system. In this case, the DC level would be offset slightly on each acquisition, depending on how the aquisition start time "beats" against the signal being measured.

Though, that also sounds plausible. Hmm... the fact that the 10us period seems to remain constant at different signal frequencies might suggest that the level is being averaged over a fixed number of samples rather than a single cycle.

That's an interesting thought, very plausible, and can be tested by sweeping the frequency of the input signal.
If this is the case,then  whenever the input signal is an integer multiple of the "settling" time, the jitter should vanish. It should then be possible to multiply the input signal by any integral value, without causing the jitter to re-appear.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 15, 2014, 02:42:04 pm
Yes, I believe it does. This whole thing seems blown a bit out of proportion to me... Jitter is always pretty bad when you go off-trigger.
The thing is that jitter on all of the other scopes in Dave's video were at least an order of magnitude better than the 1000Z series, even ye-olde DS1052E. What makes it worse is that Rigol are yet to acknowledge that a problem exists and the problem seems to be subject to variation from unit to unit. If some people have no jitter, i have 8ns and someone else has 20ns, what's the chance that there are units out there that do 50ns? 100ns? There's not much point having a 100MHz scope if a 100MHz signal turns into a complete blur (or has a significant phase offset from the actual signal when you single shot) at every multiple of 5us from the trigger point.

It's not bad enough on my unit that i would bother seeking a replacement, but it is bad enough that Rigol need to acknowledge that there is a problem and work out what is causing it so they can either fix it or ensure that it is kept to a manageable level in future units.

I performed a self-cal yesterday, makes no difference.

I had also performed a self-cal some time before that (within 24 hours) as part of my review video.

I just did a self-cal on my 1054z and also found no change to the jitter problem.  The jitter increases with increasing input frequency and is not too bad below 1MHz -- unnoticeable at 100KHz.  The jitter also increases gradually as the delay is moved from 0 to 5us then decreases from 5us to 10us, etc..    (I used an Siglent SDG1025 for my testing.)

Firmware: 00.04.01.SP2
Board: 0.1.1
Are you sure that the jitter is decreased with frequency, or simply that it is harder to observe nanosecond jitter on signals that have a very low slew rate? See my post - Reply #168. Obviously it is hard to observe 10ns of jitter on a 100KHz sine wave because when you adjust the horizontal offset to 5us and zoom in to 5ns/division the signal is almost a horizontal line. Add 10ns of jitter to that and it still looks like a thin horizontal line. Also it is almost impossible to trigger with nanosecond accuracy on a signal with such a low slew rate, due to vertical noise.

If i set my function generator to 100KHz square wave (fast rising/falling edges), adjust the horizontal offset to 5us and zoom in to 5ns/div i get a sharp falling edge that moves left and right in a sine fashion at about a 1Hz repetition rate. This indicates to me that the jitter is not random and is caused by a clock frequency modulation effect around 100KHz give or take 1Hz, or some multiple of 100KHz.

Edit: the modulation frequency must be 100KHz because if i set my signal to 200KHz i see two rising edges moving with opposite phase, and at 300KHz i get 3 falling edges moving 120deg out of phase with each other, 400KHz = 4 edges, and so forth.
At 99,999.3Hz there is no observed jitter as falling edge occurs in the same place on every capture. A 100KHz frequency modulation of the sampling clock also aligns with the observation that it only occurs at multiples of 5us from the trigger.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Codemonkey on November 15, 2014, 03:00:13 pm
FWIW, I have a DS1104Z, Software version 00.04.00 (hardware version not shown). I don't see the jitter at all when playing with the delayed trigger:

I do see jitter when using AC coupled trigger but given that I've never used that mode I'm not really all that fussed about it.

(I don't have a sig gen so used a 44MHz crystal oscillator as a source)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nixfu on November 15, 2014, 03:11:10 pm
I did not expect anyone to so badly confuse AC trigger coupling with AC input coupling. I'm pretty sure I showed I was suing the trigger menu more than once in the video, and mentioned it was trigger coupling.

Well, to be fair the menus look nearly identical between the trigger AC setting and the input AC coupling.  They are both that first menu item on the right hand side of the screen. 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: g0hjq on November 15, 2014, 03:16:27 pm
I've got a 2 week old DS1074.

I cannot find any sign of the 5uS jitter problem using an external Siglent SDG1020 at 10MHz.

It does suffer from the AC TRIGGER issue. I can't think of many circumstances where I would need to use AC triggering, so aren't really concerned about it.

Software version is 00.04.01.SP2, and board version is 0.1.1



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: megajocke on November 15, 2014, 03:35:29 pm
Basically, AC trigger coupling allows to keep trigger level at the same spot when signal reference level is moved up and down. I do not see how this could be used on or apply to digital scope.

I find AC trigger coupling useful to be able to keep the trigger level at the same point in the varying part of a waveform while changing the DC-offset. This applies to a digital scope as much as to an analog one.

I used it just a few days ago (on an Agilent scope) when looking at the clipping chacteristics of a class D amplifier by feeding the input a sine wave which I manually varied the DC offset of. Using the AC trigger mode, the scope kept triggering as I varied the offset over the full input range of the amplifier without having to twiddle the trigger level knob. Because I was able to keep the inputs DC-coupled I could see at what voltage the amplifier clipped among other things.

It's not an audio-related application, by the way. O0
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fagear on November 15, 2014, 03:49:45 pm
I have my DS2072A and DS4024 for the review, so I've checked both of them.
But I have no proper signal generator now, all I have is breadboard with ATmega8 outputting 2 MHz square wave via PWM. And this ATmega is running from internal 8 MHz clock (not even from crystal), so it is "completely unstable". ;D And can not be trusted.

DS2000A:
Problem #1 (5us huge jitter): can't confirm or decline (because of unstable signal source)
Problem #2 (AC coupled trigger huge jitter and offset): confirmed, bug is present
Problem #3 (dual slope trigger): not confirmed, works fine; it's actually the holdoff that confuses things, but there is nothing wrong with it
Problem #4 (only DC-coupled EXT trigger): confirmed, it works only with DC coupling; UI does not affect performance.

DS4000:
Problem #1 (5us huge jitter): can't confirm or decline (because of unstable signal source)
Problem #2 (AC coupled trigger huge jitter and offset): confirmed, but in a strange way... occurs when trigger level is around 0 V and on certain time bases
Problem #3 (dual slope trigger): not confirmed, works fine
Problem #4 (only DC-coupled EXT trigger): not confirmed, works fine, and problem #2 disappears at the same time!

Also I've spotted that hardware frequency counter go wild synchronous with AC coupling of the trigger. When it measures frequency of the same channel that it's  triggering of.

I've shot a video about it with all demonstrations. It is rendering now, and I am working on Russian->English translation of subtitles for it... :-/O
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 03:59:46 pm
Hmm, isn't this just a characteristic of any delayed trigger on any oscilloscope?

I had an old HP 54501A. 10MSa/s ADC. As the trigger delay increased, jitter increased. It made anything more than about 1ms completely unusable on continuous trigger mode.

This makes sense, as the distance from the trigger point increases, the jitter becomes a sum of all previous samples. At 1GSa/s, 5 microseconds is 5,000 samples. For a jitter of ~5ns, the per-sample jitter would have to be ~1ps.

To me, that sounds completely reasonable...

Does my reasoning sound right?

Except for how jitter adds your reasoning is right but the magnitude and peculiar behavior of the jitter in this case indicate that something wrong.  Long term jitter is not just simple addition of the jitter from individual cycles.

The jitter on a digital delayed timebase is the addition of the trigger jitter and the long term, not short term, clock jitter.  1ns of jitter over 5us is 200ppm which is terrible and these oscilloscopes are displaying several times that.  I ran the same test on my 2440 and the peak-to-peak jitter out to 500uS (as high as I could go at 2ns/div) was about 350ps which almost doubles the specified maximum trigger jitter of 200ps and is within its delayed timebase total jitter specification of 400ps.  That comes out to 0.7ppm combined trigger and timebase jitter over a period of 500us which seems about right to me although I do not know how much of the clock jitter came from my signal source and how much came from the oscilloscope.  The other oscilloscopes which Dave tested in his video also displayed insignificant jitter at 5us and beyond.

Even if the Rigol just had excessive long term jitter for whatever reason, that it decreased to a minimum and the expected jitter at 10us and multiples of 10us after that indicates that something other than just high long term jitter is occurring.

The problem also cannot be excessive trigger jitter which would change depending on the transition time of the trigger edge because that would be constant and not decrease with longer delays.

Yes, I believe it does. This whole thing seems blown a bit out of proportion to me... Jitter is always pretty bad when you go off-trigger.

The jitter should be worse but not this much worse and it should not get better with longer delays.

Quote
Consider: yes, it looks worse on the DS1000Z/DS2000, but these scopes also have a significantly better graded-intensity display, requiring them to capture significantly more samples and combine them into a screenful. That's naturally going to appear to amplify the jitter.

Without intensity grading multiple acquisitions the jitter is still there but is more difficult to see; the edge of the delayed waveform would look like it is jumping horizontally.  Intensity grading, variable persistence, and envelope detection make it easier to see.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 04:07:39 pm
If i set my function generator to 100KHz square wave (fast rising/falling edges), adjust the horizontal offset to 5us and zoom in to 5ns/div i get a sharp falling edge that moves left and right in a sine fashion at about a 1Hz repetition rate. This indicates to me that the jitter is not random and is caused by a clock frequency modulation effect around 100KHz give or take 1Hz, or some multiple of 100KHz.

Edit: the modulation frequency must be 100KHz because if i set my signal to 200KHz i see two rising edges moving with opposite phase, and at 300KHz i get 3 falling edges moving 120deg out of phase with each other, 400KHz = 4 edges, and so forth.
At 99,999.3Hz there is no observed jitter as falling edge occurs in the same place on every capture. A 100KHz frequency modulation of the sampling clock also aligns with the observation that it only occurs at multiples of 5us from the trigger.

I worried that this weird jitter problem with a peak at 5us and a null at 10us was just an artifact of using a DDS or synthesized signal generator but Dave ruled that out when he tested other oscilloscopes which did not display the problem.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wn1fju on November 15, 2014, 04:26:46 pm
As others may have observed, I'm certainly seeing a vast difference with the 5 us jitter when I switch signal sources.  With my HP 3314A function generator set to a 10 MHz sinewave, I'm estimating about 3 minor ticks of jitter (at the min 1104Z horizontal time/div) with the 5us delay.  When I switch the source to the ovenized 10 MHz oscillator in my HP 5335A counter, the jitter reduces to about 1-1/2 ticks.  With zero delay, both sources I estimate to be about 1-1/4 ticks (as best as I can guess).  This is all with the 1104Z set to 5 sec of persistence.  So it would seem that the accrued jitter in the source over a 5 us interval has some bearing???
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 15, 2014, 04:47:01 pm
kinda recapping it...

I did not expect anyone to so badly confuse AC trigger coupling with AC input coupling. I'm pretty sure I showed I was suing the trigger menu more than once in the video, and mentioned it was trigger coupling.

Well, to be fair the menus look nearly identical between the trigger AC setting and the input AC coupling.  They are both that first menu item on the right hand side of the screen.

nope, one menu has 3 menu items (ending with "gnd") another 4, and not ending with "gnd" item...and that is exactly how i figured instantly that it's not input coupling thing, because dave was obviously not using the coupling menu. i was like "what's that menu he's using anyway", and then went back into video, and heard him explain it was trigger menu, and that was it....

going back a bit with reported thing no1 ( thing no.2 (ac coupled trigger) we already removed as being important...albeit it's still interesting is it digital or analog...different hardware revisions having it (ie newer scopes) kinda suggest they won't be able to resolve it via firmware update(?) ):

1- if you can't use 5us(or ms), you can use 10, glass is half full again!  ;D
2- if you can miss this jitter, you're probably blind.
3- simillar to trigger ac coupling issue (usefulness/uselessness), what's the point of moving trigger horizontally so much off the screen? i mean i won't really be able to see more of a waveform no matter where i put the trigger, i have those 480pixels and that's it....
(this scope needs hdmi output and 1080p support...then they could even remove the lcd screen alotogether....   >:D )
didn't play with timings too much, but if you first need to squeeze the waveform in order to move it fast enough later (to move it by amount of 5)...meh....

the more one looks at this problem, the more it reminds to 'no-trigger curiosity', although this is a real bug, but not that damaging to scope usage.
would be cool for rigol to fix it, but how many of us would run into this issue, and how exactly/why (talking now about 'time jitter' issue).

i'll do some measurements to see if moving trigger horizontally just off the screen reveals the bug, and  if not....i'll just stop worrying...  ;)

the third issue (which deosn't really exist) was already explained by rs20 here:
https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg551012/#msg551012 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg551012/#msg551012)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: c4757p on November 15, 2014, 04:55:22 pm
I worried that this weird jitter problem with a peak at 5us and a null at 10us was just an artifact of using a DDS or synthesized signal generator but Dave ruled that out when he tested other oscilloscopes which did not display the problem.

Dave didn't rule anything out with the other oscilloscopes, because he tested them at the same points. If they also exhibit this behavior, why should it happen at the same point in time as it does on the Rigol? That will be a function of the sampling design, most likely.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: JonR on November 15, 2014, 05:03:14 pm
First off, Hi all, first post for me.

My 1054Z arrived yesterday a few hours before Dave's video :)

Lots of intersting information in this thread, will have to re-read thoroughly later. Looking after my kids today however I found some time for a tinker with the AC coupling jitter issue :)

I took the trigger output of the 1054z and looped it back up the clacker of chan2 while still triggering off chan 1 which was being fed by a function gen.

There were some intersting observations.

1. The trigger edge on CH2 (blue) always begins between ~352ns and ~360ns after the trigger indicator**
2. In DC trigger coupled mode, the CH1 (Yellow) output from sig gen is always steady, however the trigger edge jitters between 352-360ns..
3. In AC trigger coupled mode, the CH1 output from the sig gen always jitters, but the trigger edge is steady*

*Except at 12MHz and at 24MHz (+/- ~2MHz) where both the CH1 sig gen source and the CH2 trigger edge are jittering. But interestingly, not by the same offset when played back from a recording.

**I confirmed this by connecting the trig out of the 1054z into the ext trig input of my old 1052E and fed both with the same input. Sure enough, a trig offset of ~352ns was required on the 1052e to align the edges of a 10HZ square wave. Looks like the trigger hardware takes  between 350-360ns to process an incoming waveform so must need to compensate for this variance when displaying the waveform on the screen (assuming the trig out is good). /shrug

I have attached some pictures.

The source into CH1 (yellow) of the 1054z is a sinewave from a Rigol DG1022, is DC coupled with BW off.

Triggering is on CH1, Edge, Up slope, Normal sweep.

I did also notice that in the Rigol specs for the 1000Z series the pulse width range has a minimum of 8ns, which may also come into play here. Not sure, but it's right in my 352-360 ish range.

What does this all mean in terms of hardware/software? No idea! I'm just a beginner at electronics, however I thought I'd throw this in.

I don't think this is ever going to be an issue for me in reality. I never used AC triggering until this came up, however now that I know about it I'll probably find a use now :)

Jon
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: HexfeT on November 15, 2014, 05:05:55 pm
My trigger offset jitter problem no changing by offset value. 5,10,15,20,25us... always there, and same.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 15, 2014, 05:20:46 pm
and if you put the generator freq. exactly to 21mhz, not 21.0017?

seems to be getting progressively worse in your case, more you move it from centre, more jitter it gets...at 15us it's even starting to change the amplitude of the signal...

btw. you're using 1x probe on 20mhz signal, and that probe (if it's rigol default probe) doesn't have that bandwidth, so you would be using 10x in that case anyway...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 05:35:48 pm
As others may have observed, I'm certainly seeing a vast difference with the 5 us jitter when I switch signal sources.  With my HP 3314A function generator set to a 10 MHz sinewave, I'm estimating about 3 minor ticks of jitter (at the min 1104Z horizontal time/div) with the 5us delay.  When I switch the source to the ovenized 10 MHz oscillator in my HP 5335A counter, the jitter reduces to about 1-1/2 ticks.  With zero delay, both sources I estimate to be about 1-1/4 ticks (as best as I can guess).  This is all with the 1104Z set to 5 sec of persistence.  So it would seem that the accrued jitter in the source over a 5 us interval has some bearing???

Assuming that the clock jitter from the source and clock jitter from the oscilloscope uncorrelated (*), the displayed waveform will show the root sum of squares of the jitter from both sources so to make this measurement, the long term jitter over the period of interest from the signal source needs to be low.  In general any crystal oscillator should work but some synthesized or DDS sources may have problems at certain output frequencies.

If the measurement is made using peak-to-peak jitter, then they will directly add but this does not change the requirements on the source.

(*) Agilent made some DSOs which modulate the sampling clock to deliberately prevent accidental correlation between the sample rate and input signal but this is compensated for before the waveform is displayed so it is transparent to the user and the results look like any other DSO with a uniform sampling clock.  Correlation between the signal and sampling clock prevents equivalent time sampling for operating correctly.

I worried that this weird jitter problem with a peak at 5us and a null at 10us was just an artifact of using a DDS or synthesized signal generator but Dave ruled that out when he tested other oscilloscopes which did not display the problem.

Dave didn't rule anything out with the other oscilloscopes, because he tested them at the same points. If they also exhibit this behavior, why should it happen at the same point in time as it does on the Rigol? That will be a function of the sampling design, most likely.

While this is possible, I think he would have noticed and told us if there was excessive jitter at points other than 5us on the other oscilloscopes.  I assume he left it out of his video for brevity and because there was nothing to see.

I would consider it very odd if a Tektronix or Agilent oscilloscope displayed this behavior since one of the advertised applications for their DSOs is measuring long term jitter.  Users may not commonly use low end Rigol oscilloscopes for long term jitter analysis but they sure use Tektronix and Agilent oscilloscopes for it and a problem like this would have been noticed.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 05:56:25 pm
1. The trigger edge on CH2 (blue) always begins between ~352ns and ~360ns after the trigger indicator**

Thanks for sharing this and your other results.

I did not know the trigger output delay was that long but I expected about that much jitter.  Rigol only discusses using the external trigger output to verify the waveform acquisition rate and for automation and not for precision timing or triggering.

Quote
2. In DC trigger coupled mode, the CH1 (Yellow) output from sig gen is always steady, however the trigger edge jitters between 352-360ns..
3. In AC trigger coupled mode, the CH1 output from the sig gen always jitters, but the trigger edge is steady*

They may only be related by a common processing clock inside the FPGA.  This does point toward an FPGA programming problem causing the AC trigger coupling jitter which can be updated through firmware.  I doubt anything can be done about the jitter or delay in the external trigger output and I am not sanguine that the jitter at a delay of 5us can be repaired easily.

Quote
*Except at 12MHz and at 24MHz (+/- ~2MHz) where both the CH1 sig gen source and the CH2 trigger edge are jittering. But interestingly, not by the same offset when played back from a recording.

There is likely a corner case where the external trigger output jumps between its two extreme positions.

Quote
**I confirmed this by connecting the trig out of the 1054z into the ext trig input of my old 1052E and fed both with the same input. Sure enough, a trig offset of ~352ns was required on the 1052e to align the edges of a 10HZ square wave. Looks like the trigger hardware takes  between 350-360ns to process an incoming waveform so must need to compensate for this variance when displaying the waveform on the screen (assuming the trig out is good). /shrug

I would be carefully paranoid about relying on low jitter from the external trigger input but the 1052e is an older design and probably works fine.

Quote
I did also notice that in the Rigol specs for the 1000Z series the pulse width range has a minimum of 8ns, which may also come into play here. Not sure, but it's right in my 352-360 ish range.

This probably provides insight into the clock frequency used inside the FPGA for processing the trigger.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Owen on November 15, 2014, 06:23:53 pm
I've tested my DS2000 Series using AC coupling Mode on the trigger: I've fed in a sine wave with 500 mV offset and frequency of 1 MHz, but didn't terminate it proper. And it looks okay so far, if i'm getting higher with frequency it starts jittering around. So with signals less than < 1 MHz there is no jitter. If I really need to use AC coupling Mode i would probably use the avarage mode (32 Samples) and just filter it this way. But to be honest i've never used that AC trigger coupling mode before :).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fagear on November 15, 2014, 07:25:00 pm
Sorry, I'm helpless with English translation in Youtube editor... Takes too much time. |O
I hope, it will be clear without translation. :palm:
??????? ????????????? ????????????? Rigol (https://www.youtube.com/watch?v=bVg-lpLwmKc#)

03:57 - my "signal source"
04:56 - testing for problem #1 on DS2000 (can't check it, bad signal source)
08:07 - testing for problem #2 on DS2000 (confirmed)
11:14 - testing for problem #3 on DS2000 (not confirmed)
13:27 - testing for problem #4 on DS2000 (confirmed)
18:43 - testing for problem #1 on DS4000 (can't check it, bad signal source)
19:37 - testing for problem #2 on DS4000 (confirmed in a strange way)
22:47 - testing for problem #3 on DS4000 (not confirmed)
23:02 - testing for problem #4 on DS4000 (not confirmed)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 07:54:08 pm
I don't know Russian but I could understand a lot of it, nice video   :-+
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 15, 2014, 08:45:24 pm
A DS2072A here with HW v2.0. Practically no 5us trigger offset jitter. AC coupling trigger jitter does present.

Do not know if this helps or makes it more puzzling but accidentally discovered that AC Coupled trigger jitter is cured if to set trigger type from Edge to Runt or Window type (play with trigger  level controls to stop the jitter). Please check on yours.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 15, 2014, 09:01:17 pm
I think only Edge triggering supports AC coupled trigger.
At least on mine that's the only one that has the option.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 15, 2014, 09:54:55 pm
I now see what you mean. With trigger type set to Runt or Window, trigger coupling DC/AC selection tab disappears.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: silicon_ghost on November 15, 2014, 09:55:49 pm
I just tested this on my Rigol DS4024 scope (channel 1 only).  I see a little bit of what Dave Jones demo'd in the video.  I don't see any difference from AC or DC coupled triggering so I'm only showing DC coupled trigger screen prints.

I fed in 5 and 50 MHz square waves from a Rigol DG4162.  I played with plenty of combinations of DC or AC trigger coupling, trigger delays from 0 to ~10 us, and different timebases.  You will see that the transition from clean to jittered triggering is dependent on the timebase used.

Scope details
- DS4024
- S/W Ver 00.02.01
- H/W Ver 1.2
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wn1fju on November 15, 2014, 09:57:14 pm
All I know is that I tried the following signal generators (all at 20 MHz):

HP 3314A
Wavetek 288
HP 3335A
HP 8782A

The first two are generic function generators and the last two are RF synthesizers with ovenized oscillators.

These four were all tried against the following digital scopes:

Rigol DS1104Z
HP 54610B
HP 54112D
Fluke PM3390B
Tek TDS350

Every scope but the Tek showed the following:

no jitter at 0 delay with any of the four sources
plenty of jitter at sufficient nonzero delay, but ONLY with the first two function generators
no jitter at sufficient nonzero delay with the two RF ovenized synthesizers

Now, all the non-Rigol scopes use equivalent time sampling and it seems clear that in the absence of a stable source, such as the synthesizers, the combination of sampling and delay leaves one with a "jittered" presentation after the wandering waveform builds up.

Apparently, the Rigol is doing some analog of equivalent time sampling (???) since I get exactly the same behavior - OK only with the synthesizer sources.   

Incidentally, the Tek scope passes the test because it cheats - it won't let you set the delay large enough to cause a problem.

Anyway, I feel a lot better now knowing that my 1980-1990 scopes are just as good as my 2014 scope!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 15, 2014, 09:58:14 pm
My trigger offset jitter problem no changing by offset value. 5,10,15,20,25us... always there, and same.

What was your signal source?  If the source has that much long period jitter anyway, then the oscilloscope is just going to show that.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: HexfeT on November 15, 2014, 10:17:13 pm
I don't have a signal generator. Source is STM32F4 Discovery kit. Using PWM module. 84Mhz bus clock from mcu's pll, PWM module configured bus frequency/4, %50 duty.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: frogmaster on November 15, 2014, 10:34:21 pm
Sorry, I'm helpless with English translation in Youtube editor... Takes too much time. |O
I hope, it will be clear without translation. :palm:

Thanks for the vid. I tried to translate it on the fly. My Russian is rather crusty and my English is rather freestyle (and I'm not becoming interpreter, that's for sure  :phew:). Can't comment on the vid, so I hope I can dump it here.

Code: [Select]
Hi all,

not long ago

the widely known video blogger Dave Jones from Australia (not Austria),
who runs the EEVBlog site corresponding channel on youtube site
recorded a problem with devices Rigol DS1000Z and DS2000(A)
the issue specifically concerns its 'synchronization systems' {trigger}
I don't have the (1000) device here now, I got it (lend)

but, as you can see, I do have the DS2000 so I'll try to make it with this one just as Dave Jones has shown in his video. Aside the DS2000, I temporarily have the DS4000 which is a bit more expensive than the DS2000. Let's see if the DS4000 has some similar problem or not.

About the Version: [version info]

Dave named three main problems:
    1. when DC coupling
        jitter occurring at multiples of 5us
    2. when AC coupling
        1. synchro point drifts away
        2. jitter independent of signal frequency and/or form
    3. --

I don't have a signal gen at hand- but I do have an ATmega and I can, independently of the quality of the mega-generated signal, demonstrate the very same problems Dave has shown.

[demo of problems follows]

    1. confirmed
        5us problem -> jitter 10ns
        10us: jitter should disappear now, but I can still see it, so I conclude that the (ATmega) signal is simply not fancy enough. (Thus, I can neither confirm nor ...)
    2. with DC coupling we can nicely see the signal,
    now turning on AC coupling we can't see anything. let's zoom out. we should now see the edge in the center of the screen, what we do see a fairly big misalignment here  (->incorrect)

[citing rigol forum response]

I personally never used the AC coupling (and can't really imagine {think of a way} using it). Otherwise the scope works reasonably well and if it wasn't for Dave wouldn't have noticed that problem.

    3. Can't observe the problem Dave had. I could imagine that Dave's signal somehow interfered with the holdoff value. E.g. If I change my holdoff value here, I can reconstruct a similar 'situation'. But it doesn't say anything about the proper working of the scope.

[describing how the edge falls into the 'holdoff time']

Thus I can conclude that this 'problem' is not a problem with the scope but a problem with the particular setup {the way its user set up the scope}.

[around 13min]

Trying to reproduce the problems Dave describes I found another problem. Given this specific device that supports external triggering. I'm triggering *the same signal* over the EXT trigger. Firstly, we observe an offset of 10ns. The real signal's pk-pk value is 5V, so considering the fact that the probe is x10 the center is around 2.5V [seeing 254mV]. As soon we're moving the trigger value below 0 {below the signal}, sync breaks down (trigger goes beserk). As soon we're above 440mV {i.e. above 5V}, same thing.

Now let's change to AC trigger. Nothing changed. So there's no way of really triggering AC-style. (There's no AC trigger function.) Rigol could've just left that option out.

[summing up stuff]

[same procedure, 4 problem checks on the DS4024]
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: JDubU on November 16, 2014, 01:20:30 am
DS2072 (not A version)
HW version: 2.0
Firmware: 00.03.01.00.04 (latest available)

Signal Source:  Epson SG-615P 7.3728MHz 100ppm crystal oscillator module.

Multiple of 5us delay issue:  No visible jitter at all for any delay
AC trigger issue:  Approx. 8ns jitter

Note:  I first tried using a 2.5MHz PWM timer output from a STMF4 Discovery board as a signal source but that signal had a consistent 25ns jitter.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 16, 2014, 01:57:49 am
no jitter at 0 delay with any of the four sources
plenty of jitter at sufficient nonzero delay, but ONLY with the first two function generators
no jitter at sufficient nonzero delay with the two RF ovenized synthesizers

Function generators usually have high long period jitter so this is not unexpected.

Quote
Now, all the non-Rigol scopes use equivalent time sampling and it seems clear that in the absence of a stable source, such as the synthesizers, the combination of sampling and delay leaves one with a "jittered" presentation after the wandering waveform builds up.

Variable persistence or envelope mode can be used with equivalent time sampling to show the jitter.

Quote
Apparently, the Rigol is doing some analog of equivalent time sampling (???) since I get exactly the same behavior - OK only with the synthesizer sources.

They have to do something to get better than 4ns timing resolution at 250MS/s.  I think they measure the trigger to sample time after interpolation which can be done in FPGA logic.  This is just another way to do equivalent time sampling with a digital trigger.

Quote
Incidentally, the Tek scope passes the test because it cheats - it won't let you set the delay large enough to cause a problem.

I could not find much on the TDS350 but it looks like a striped down TDS460.

Quote
Anyway, I feel a lot better now knowing that my 1980-1990 scopes are just as good as my 2014 scope!

The difference is your 1980-1990 oscilloscopes cost 20 times more.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: HexfeT on November 16, 2014, 03:12:49 am
My trigger offset jitter problem no changing by offset value. 5,10,15,20,25us... always there, and same.

What was your signal source?  If the source has that much long period jitter anyway, then the oscilloscope is just going to show that.

Ok, i understand now, signal source stability is very important. I found a crystal oscillator and test again. Results are good now.

DS1054Z
SW: 00.04.01.SP2
HW: 0.1.1
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Matthias Toussaint on November 16, 2014, 10:18:12 am
I know there's been little to no discussion of the dual-slope triggering "bug" mentioned in the video, but I just wanted to point out that this is not a bug at all, rather an artefact caused by trigger holdoff working correctly.

So I put together a quick little video explaining how trigger holdoff causes the observed behaviour -- and I also show how holdoff (even the default, minimum setting) could cause real confusion even if you're using normal edge triggering. This is not Rigol specific, this applies to any scope (with a trigger). With the DS2202 @ factory default settings, these problems could potentially (in admittedly somewhat contrived circumstances) bite you at frequencies as low as 5 MHz.

Oscilloscope triggering holdoff trap (https://www.youtube.com/watch?v=O8zJAdu7Trs#ws)

Why do the DS1000Z and DS2202 behave differently in the EEVBlog video? Because the default(=minimum) holdoff of the DS1000Z, 16ns, is less than the 100ns of the DS2202. 16ns fits inside a 20 MHz pulse (25 ns), 100ns does not. Neither is right nor wrong, and both can be configured to behave as desired.

I made a quick test with a DS4054 and the effect can not be observed there. Dual slope trigger is stable and does not change with holdoff. I believe your explanation is correct, I'm just wondering how they made it work on the DS4000.

BTW: I also can't see AC coupling problems on my scope

http://youtu.be/Z6i9-pQ-kNk (http://youtu.be/Z6i9-pQ-kNk)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 16, 2014, 12:09:05 pm

I made a quick test with a DS4054 and the effect can not be observed there. Dual slope trigger is stable and does not change with holdoff. I believe your explanation is correct, I'm just wondering how they made it work on the DS4000.

BTW: I also can't see AC coupling problems on my scope

http://youtu.be/Z6i9-pQ-kNk (http://youtu.be/Z6i9-pQ-kNk)

Your video is marked private, so we can't watch!

If your talking about the delay jitter, I found it on my 4000:

MSO4054 at various delays and beyond, sorry for the ultra crappy webcam footage.  (firmware = 2.02.SP1, hardware version = 1.3)

20Mhz, square, 5Vpp, AC/DC coupling has no effect.

MSO4054 delay jitter (https://www.youtube.com/watch?v=2-mQ6TWP13A#ws)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 16, 2014, 12:43:52 pm
If your talking about the delay jitter, I found it on my 4000:

MSO4054 at various delays and beyond, sorry for the ultra crappy webcam footage.  (firmware = 2.02.SP1, hardware version = 1.3)

20Mhz, square, 5Vpp, AC/DC coupling has no effect.

MSO4054 delay jitter (https://www.youtube.com/watch?v=2-mQ6TWP13A#ws)

This looks like a different problem then the one Dave documented.  The jitter is roughly equal at 1us of delay and longer instead of vanishing at 10us; long period jitter does not appear to increase until much higher delays.

What was the signal source?  This is the kind of result I might expect when using a dithered 1 GS/s DDS to produce square waves.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Marc M. on November 16, 2014, 01:16:11 pm
....What was the signal source?
 Did you try making small variations to the frequency?
I don't think anybody gave you a direct answer when you asked about this earlier. If they did, I apologize for being redundant.  I used a Rigol DG4162 set to a 15 MHz sine wave, 3Vpp, 0V offset and got the same behavior on my Rigol DS2072 with the trigger set to AC coupling.  I then varied the frequency by Hz, 10's of Hz, 100's, etc. up a couple of MHz.  Other than changing the pattern of the displayed jitter, it had no effect on the amount of jitter.  As a second source I used the RF output of a Rohde & Schwarz CMU-200 Univ. Radio Tester clocked by an external rubidium standard.  I tried 10, 13, 15, 16, 19, & 20 MHz and all exhibited the same behavior so I don't believe it's frequency dependent.  Like others, setting low freq. rejection reduced the amount of jitter by about 1/2 or so but didn't eliminate it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 16, 2014, 01:19:30 pm

What was the signal source?  This is the kind of result I might expect when using a dithered 1 GS/s DDS to produce square waves.

In the video above it's a DG4000, but I replicated the jitter with a 20Mhz OCXO as well. 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 16, 2014, 03:20:59 pm
Playing around some more.  Notice how memory depth/averaging change the artifact behaviour.

Also notice when scope is stopped, horizontal position changed, the artifacts disappear.

(MSO4054, random 16Mhz TCXO, DC trigger coupling, 100us delay is roughly the worst point, does not disappear every 5us like Dave's, self cal last night - think Rigol mentioned doing this)

MSO4054 delay jitter #2 (https://www.youtube.com/watch?v=A5hMbiL83BA#ws)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: open loop on November 16, 2014, 04:09:48 pm
Have read about 70% of all the posts so apologise for mentioning anything that has already been discussed. Couple of ideas...

Could it be anything to do with the intensity graded display, what happens when the intensity graded display is switched off? I know it sounds unrelated but you never know  :-//

Another thing to try for the 5us issue is to feed the same signal into channels 1 and 2 then trigger off channel 2 experiment with the coupling on this channel and see if it possible to do AC trigger either using channel 2 AC signal coupling or AC trigger coupling...

Interesting to note that the AC Trigger coupling issue was never really noticed for two years on the well loved Rigol 2000 series.  As there is an option for AC trigger coupling I would have thought that Rigol would have a test case for it.  It just goes to show that scopes are getting so complicated that even the manufacturers are missing things. I bet even the Agilent/Tektronix have bugs in the "Fringe" capabilities of their scopes.  :-BROKE

I am seriously considering upgrading my DS1052E to a DS1000z series and this has not really changed my mind as I have never used AC coupling on triggering before. I would be very happy with a new ds1000z series, a lot of scope for the price and it seems that Rigol are keen to address issues when they come up. Fortunately the Rigol distributer is 20mins drive from my home  :box:


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: iDandelions on November 16, 2014, 04:21:49 pm
I've just been messing around with the in-built calibration signal on my MSO2072A as I don't have a sig gen. I was looking at the seemingly random ability of the scope to trigger on both rising and falling slopes. I noticed that switching the display type between vectors and dots alters the result of the trigger. It doesn't always do it, but I'm surprised it affects the trigger.

https://www.dropbox.com/s/vltg0dmwr2fc5kw/MSO2072A_20141116-160429.png?dl=0 (https://www.dropbox.com/s/vltg0dmwr2fc5kw/MSO2072A_20141116-160429.png?dl=0)

https://www.dropbox.com/s/09q1wkh4ndxif66/MSO2072A_20141116-160445.png?dl=0 (https://www.dropbox.com/s/09q1wkh4ndxif66/MSO2072A_20141116-160445.png?dl=0)

(added screen shots as links as I can't get the img tag to work)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: electronic_eel on November 16, 2014, 04:22:03 pm
Playing around some more.  Notice how memory depth/averaging change the artifact behaviour.

Also notice when scope is stopped, horizontal position changed, the artifacts disappear.

(MSO4054, random 16Mhz TCXO, DC trigger coupling, 100us delay is roughly the worst point, does not disappear every 5us like Dave's, self cal last night - think Rigol mentioned doing this)
Do you have a 10MHz reference available? Would you mind testing it again with an external 10 MHz?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 16, 2014, 04:46:10 pm
Playing around some more.  Notice how memory depth/averaging change the artifact behaviour.

Also notice when scope is stopped, horizontal position changed, the artifacts disappear.

(MSO4054, random 16Mhz TCXO, DC trigger coupling, 100us delay is roughly the worst point, does not disappear every 5us like Dave's, self cal last night - think Rigol mentioned doing this)
Do you have a 10MHz reference available? Would you mind testing it again with an external 10 MHz?

No problem, 10Mhz OCXO:

MSO4054 delay jitter #3 (https://www.youtube.com/watch?v=cMnKDM2UBsI#ws)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: electronic_eel on November 16, 2014, 04:52:01 pm
No problem, 10Mhz OCXO:
thank you. but it seems I wasn't clear enough:

Please feed the 10 MHz from the OCXO into the external reference input on the back of the scope. You then have to select Reference Clock Input in the utilty menu.
Then measure e.g. the same 16 MHz TCXO from the video before.

This way we can see if the reason for the jitter is jitter from the internal oscillator of the scope.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: HexfeT on November 16, 2014, 04:53:55 pm
Playing around some more.  Notice how memory depth/averaging change the artifact behaviour.

if you change memory depth, changes how much waveform captured and displayed. Long memory depth mean less waveform capturing.

Also notice when scope is stopped, horizontal position changed, the artifacts disappear.

This is normal. When you stopped, only one waveform trace displaying.

if different trigger offset value no affect displayed waveform, jitter is not periodycally come and go (like dave's) probably your signal source is bad.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 16, 2014, 05:03:07 pm
No problem, 10Mhz OCXO:
thank you. but it seems I wasn't clear enough:

Please feed the 10 MHz from the OCXO into the external reference input on the back of the scope. You then have to select Reference Clock Input in the utilty menu.
Then measure e.g. the same 16 MHz TCXO from the video before.

This way we can see if the reason for the jitter is jitter from the internal oscillator of the scope.

Gotcha, Scope is using external GPSDO already, and was in place in all of my videos.  Scope internal oscillator or external GPSDO does not appear to have any effect.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 16, 2014, 05:05:18 pm
This is normal. When you stopped, only one waveform trace displaying.

I don't  think so, the artifact does not disappear when stopped.  Only disappears when I change the horizontal position when stopped.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: HexfeT on November 16, 2014, 05:11:14 pm
This is normal. When you stopped, only one waveform trace displaying.

I don't  think so, the artifact does not disappear when stopped.  Only disappears when I change the horizontal position when stopped.

Because when you stopped, displaying last multiple traces same time. When you change horizontal position, displaying last one.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 16, 2014, 07:04:24 pm
So on the first problem of moving the trigger point 5 us in the past, it is clear that the signal source has a lot to do with the jitter and extremely stable signals might not show the problem.

How does that explain that other scopes don't show that problem? and is the signal really that bad that jitters by that much?

Furthermore why will a bad input signal correct itself at exactly 5 us extra? I can see that happen one in a million sources that has some harmonic at 10 KHz (if my math is right on the frequency for 10 us), Or maybe the if the same function generator was used and it has that harmonic in their design. But that will show up in other scopes as well.

Edit: I hope Rigol finds and fixes the problem. I also hope Rigol don't mask the problem by just making it look like it works, then we won't be able to capture real jitter, but that should be easy to test when/if they do fix the problem so I doubt they will take that approach.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 16, 2014, 07:07:02 pm
Interesting to note that the AC Trigger coupling issue was never really noticed for two years on the well loved Rigol 2000 series.  As there is an option for AC trigger coupling I would have thought that Rigol would have a test case for it.
Again, as has already been mentioned more than once on the forum: the AC-coupled trigger jitter on the DS2000 was already noticed, reported, and talked about here (https://www.eevblog.com/forum/testgear/first-impressions-and-review-of-the-rigol-ds2072-ds2000-series-dso/msg255722/#msg255722) about a year and a half ago. We also discussed the trigger offset problem (https://www.eevblog.com/forum/testgear/first-impressions-and-review-of-the-rigol-ds2072-ds2000-series-dso/msg256168/#msg256168) (which Dave didn't mention) with the AC-coupled trigger.

I'm sorry Dave was having a brain aneurysm, but he wasn't reporting anything about the DS2000 that most of us older owners of the DSO didn't already know.

It would be nice if Rigol fixed it - but in the list of bugs that need(ed) fixing on the DSO it didn't/doesn't rank high. Just use DC coupling and manually adjust the level.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: NANDBlog on November 16, 2014, 08:14:21 pm
I believe I seen very similar DC triggering issues with TEK TDS2000 scopes a few years back. When the trigger wasnt on the screen it had more jitter than when it was on the screen. I remember, because we based design decisions on this, and we almost got burned.
And also, I believe that problem was fixed with a firmware update.

I'm curious, this case: Is there any SMPS in the scope working at 100Khz? Is it possible that the internal 10Mhz reference signal has this jitter? This is where your universal counter would come handy, Dave.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alank2 on November 16, 2014, 09:06:21 pm
Could it be anything to do with the intensity graded display, what happens when the intensity graded display is switched off?

This is what I wonder.  I'm not sure if the intensity grading can be turned off, can it?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 16, 2014, 09:10:17 pm
So on the first problem of moving the trigger point 5 us in the past, it is clear that the signal source has a lot to do with the jitter and extremely stable signals might not show the problem.

The signal source itself needs to have low long period jitter (at 5 us, 10 us, etc.) for a problem with the oscilloscope itself to show up.  If the signal source jitter is high, then a problem with the oscilloscope will be masked.

Quote
How does that explain that other scopes don't show that problem? and is the signal really that bad that jitters by that much?

The jitter at 5 us and at intervals of 10 us after that appears to be frequency modulation of the DSO sampling clock at 100 kHz and apparently does not affect all units.

Quote
Furthermore why will a bad input signal correct itself at exactly 5 us extra? I can see that happen one in a million sources that has some harmonic at 10 KHz (if my math is right on the frequency for 10 us), Or maybe the if the same function generator was used and it has that harmonic in their design. But that will show up in other scopes as well.

It could be a problem in the signal source but the other oscilloscopes did not show it.

If the signal source or the oscilloscope sampling clock is frequency modulated at 100 kHz, what happens is that for half of the 100 kHz cycle or 5 us, the average frequency may be off by x amount.  During the next half cycle, the average frequency will be off by -x amount.  Over both halves of the complete cycle of modulation, the errors cancel out so there is no error at 10 us and multiples of 10 us.  The error at 5 us and 10 us increments after that is from the odd number of half cycles of modulation which do not cancel out.

Now the above might seem contrived but some clock sources are deliberately designed to be modulated for EMC (electromagnetic compliance) reasons and 100 kHz is a common modulation frequency in this application.  This is usually referred to as spread spectrum clocking:

http://en.wikipedia.org/wiki/Spread_spectrum#Spread-spectrum_clock_signal_generation (http://en.wikipedia.org/wiki/Spread_spectrum#Spread-spectrum_clock_signal_generation)

Rigol might accidentally have used a clock oscillator which includes clock spreading or it could have happened in other ways.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 16, 2014, 09:13:04 pm
Could it be anything to do with the intensity graded display, what happens when the intensity graded display is switched off?

This is what I wonder.  I'm not sure if the intensity grading can be turned off, can it?

From 0-100% it doesn't appear to alter the quantity/size/shape of the artifacts.  No off switch that I can find.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 16, 2014, 09:17:11 pm
Could it be anything to do with the intensity graded display, what happens when the intensity graded display is switched off?

This is what I wonder.  I'm not sure if the intensity grading can be turned off, can it?

From 0-100% it doesn't appear to alter the quantity/size/shape of the artifacts.  No off switch that I can find.

Increasing the trigger holdoff may have the effect of disabling intensity grading.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on November 16, 2014, 09:47:12 pm
Thanks David,

Yeah the inverse of 0.00001 seconds it's indeed 100KHz  back to school for me :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Loboscope on November 16, 2014, 10:18:19 pm
My DS1104Z (bought some month ago at Batronix, calibratetd before testing, Firmware 00.04.01.SP2, Board Rev. 0.1.1) shows the AC-Trigger issue, but doesen´t show the 5µs Delay-Jitter, tested with different frequencies (Signal source: Siglent SGD1025, connected directly with BNC-BNC coax-cable). The AC-Trigger is only relevant for freqencies higher than 1 MHz and gets worst with shorter horizontal settings as expected. LPF reduces the jitter, averaging supresses it perfectly.
Also by moving the AC-Trigger Point upwards to the maximum level of the signal on the screen, just before trigger gets lost (for example the top of the overshoot of a square wave) I can eliminate the jitter entirely. This indeed is a behavior I that is common on my older analogue scope (Philips PM 3055), there I often have to adjust the trigger level to achieve a stable picture. With trigger set to DC the test-signals will always be stable on my DS1104Z.
Frequency Counter works allways correct.

The AC-Triggering-issue obviously semms to be a common problem spread over different Rigol-scope-models, but the delay-issue seems not to be common. If my observation is correct, concerning the DS1kZ-Series, all of the DS1054Z mentioned in this thread show this issue, but only few to none DS1074Z and DS1104Z (like mine).

This lets me raise a theory: Could this issue be caused by spreading of specs of some parts on the boards? Therewith I mean, that when Rigol does a final testing of the boards as quality check at the end of the manufactoring process there maybe some boards rejected due to not reaching the specs to a margin of lets say 100%. But imagine (most of these) these boards are not defect, but only not good enough to be sold as 70 or 100 MHz boards. If there was a appreciable number of rejected but not defective boards maybe Rigol decided to sell them as 50 Mhz boards, the DS1054Z.
They will work up to this frequency but will not be accurate enough to met the specs of his predecessors. Who of the normal users of the DS1054Z can really carry out measurements of this precision to find out these certainly only very small differences - and from a practical view they would certainly never matter in normal use. It matters only Rigol to classify the different models.

BUT could this theory explain this observed phenomenon?
What will say the experts here in this forum whose knowledge i really admire?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 16, 2014, 10:29:10 pm
Increasing the trigger holdoff may have the effect of disabling intensity grading.

On my DS2202, the ac trigger issue persists identically in both these scenarios:
- Holdoff set to 1s
- Manually mashing the single shot button
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on November 16, 2014, 11:42:47 pm
Ok   with early DS2000,   SN  < 00350

Back on July 3 ,2013 I sent Rigol North American this
----------------------------------------------------------------------------------------------
Hello Jason and Joel
 
Here is a report of a Small bug on the Rigol DS2000 with latest Firmware 00.01.01.00.02
I think this Bug is in previous FW also.
 
FW 00.01.01.00.02
A small Bug also associated with the Trigger setting of AC Coupling
Note  Wim13 has already reported that there is large Trigger Jitter when this mode is selected

I appears that also in this mode of AC coupled Trigger,
the Display of the waveform is NOT in the  correct position.
The waveform position is 50nSec to the left (early)
The offset in a fixed amount of time 50nSec
The Offset position changes at each timebase setting to be = 50nSec!!

But when the trigger is DC coupling the Position is correct.at the center of the Display

------------------------------------------------------------------------------------------------------------------

The FW is now 00.03.01..... 

So I guess It was very low on the bug fix list at Rigol,  with the MSO, DS1000, 2000A models coming out


--------------------------------------

PS   using a "T" connector to the External Trigger on AC coupled triggering I see a more stable display
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 17, 2014, 03:42:26 am
Thanks David,

Yeah the inverse of 0.00001 seconds it's indeed 100KHz  back to school for me :)

I have run across this problem before where a clock source is inadvertently frequency or phase modulated by some other signal.  Looking for the nulls or shortest period of time over which the clock returns to the correct position reveals the frequency of the interference.  An oscilloscope is one of the more common tools which can be used to directly observe this but spectrum analyzers and some frequency counters are better in a lot of cases.  The FFT display from one of the bad Rigols might reveal something.

I broke out my clipboard to make sure that the math matched the observations.

The AC-Triggering-issue obviously semms to be a common problem spread over different Rigol-scope-models, but the delay-issue seems not to be common. If my observation is correct, concerning the DS1kZ-Series, all of the DS1054Z mentioned in this thread show this issue, but only few to none DS1074Z and DS1104Z (like mine).

This lets me raise a theory: Could this issue be caused by spreading of specs of some parts on the boards? Therewith I mean, that when Rigol does a final testing of the boards as quality check at the end of the manufactoring process there maybe some boards rejected due to not reaching the specs to a margin of lets say 100%. But imagine (most of these) these boards are not defect, but only not good enough to be sold as 70 or 100 MHz boards. If there was a appreciable number of rejected but not defective boards maybe Rigol decided to sell them as 50 Mhz boards, the DS1054Z.

I would consider this more of a functional flaw than a deviation from the specifications.  The problem might be as simple as a part substitution or a configuration mistake.

Quote
They will work up to this frequency but will not be accurate enough to met the specs of his predecessors. Who of the normal users of the DS1054Z can really carry out measurements of this precision to find out these certainly only very small differences - and from a practical view they would certainly never matter in normal use. It matters only Rigol to classify the different models.

I cannot see DSOs being graded for this sort of specification.  Low jitter clocking is well understood and the magnitude of the problem here is relatively large.

Measuring long period jitter is one of the things DSOs should do well and even a 50 MHz one with a 7 nanosecond rise time should be able to resolve timing to better than a nanosecond.  Good analog oscilloscopes could have a jitter of about 250 picoseconds at a delay time of 5 microseconds which is significantly better than that displayed on the Rigols having problems.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 17, 2014, 05:30:37 am
An oscilloscope is one of the more common tools which can be used to directly observe this but spectrum analyzers and some frequency counters are better in a lot of cases.  The FFT display from one of the bad Rigols might reveal something.

I had a look just using the scopes own FFT, but could not see any difference.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on November 17, 2014, 06:19:23 am
the DS1054Z arrived today.

One more data point:
Software version: 00.04.02.SP3
Board version: 0.1.1

Got teh jitters.
But also got >100MHz bandwidth too after applying some codes.


What a sensational DSO for the up and coming EE kids who are playing with Arduino/R-Pi/Pics/etc/etc
and inventing a new world as fast as they can!



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 17, 2014, 11:15:55 am
Back on July 3 ,2013 I sent Rigol North American this
----------------------------------------------------------------------------------------------
Hello Jason and Joel

FYI, Joel no longer works for Rigol.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rf-loop on November 17, 2014, 11:49:51 am
the DS1054Z arrived today.

One more data point:
Software version: 00.04.02.SP3
Board version: 0.1.1

Got teh jitters.
But also got >100MHz bandwidth too after applying some codes.


What a sensational DSO for the up and coming EE kids who are playing with Arduino/R-Pi/Pics/etc/etc
and inventing a new world as fast as they can!

And what is your sinewave  quality (specifications)  in picture 1 and 2.
Do you know how much it have jitter measured over 5us time period.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 17, 2014, 12:14:11 pm
there was some discussion about is this a hardware or software issue:
but how would you achieve this in software alone?
are those spread-spectrum clocks configurable by software?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: han on November 17, 2014, 01:12:42 pm
did ac coupling trigger jitter intensity change if the trigger level changed?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tequipment on November 17, 2014, 02:39:00 pm
Hello everyone.  I am not sure if you saw the Rigol response back.  If not here it is:

https://www.tequipment.net/assets/1/7/EEVBlog_message1.pdf (https://www.tequipment.net/assets/1/7/EEVBlog_message1.pdf)

Thanks
Evan Cirelli

TEquipment.NET

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 17, 2014, 02:53:02 pm
Got teh jitters.
But also got >100MHz bandwidth too after applying some codes.

The jitter at 10us matters as well because if it is high there, then either the test source is noisy or there is a different problem.

[/quote]
there was some discussion about is this a hardware or software issue:
but how would you achieve this in software alone?
are those spread-spectrum clocks configurable by software?

Some of them are.  The oscillators often have an input which sets the mode and the same applies to PLL clock generators which support this function.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jlmoon on November 17, 2014, 03:10:13 pm
Interesting to note that the AC Trigger coupling issue was never really noticed for two years on the well loved Rigol 2000 series.  As there is an option for AC trigger coupling I would have thought that Rigol would have a test case for it.
Again, as has already been mentioned more than once on the forum: the AC-coupled trigger jitter on the DS2000 was already noticed, reported, and talked about here (https://www.eevblog.com/forum/testgear/first-impressions-and-review-of-the-rigol-ds2072-ds2000-series-dso/msg255722/#msg255722) about a year and a half ago. We also discussed the trigger offset problem (https://www.eevblog.com/forum/testgear/first-impressions-and-review-of-the-rigol-ds2072-ds2000-series-dso/msg256168/#msg256168) (which Dave didn't mention) with the AC-coupled trigger.

I'm sorry Dave was having a brain aneurysm, but he wasn't reporting anything about the DS2000 that most of us older owners of the DSO didn't already know.

It would be nice if Rigol fixed it - but in the list of bugs that need(ed) fixing on the DSO it didn't/doesn't rank high. Just use DC coupling and manually adjust the level.

As a a old DS2202 owner I remember the previous post as well.  One reason I just threw my 2202 in my field kit and chose to keep my Agilent stuff cozy and warm in my lab environment.  The Chinese equipment is not ready for the rigors of serious lab grade analysis and testing ... yet!!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Maxlor on November 17, 2014, 03:29:37 pm
Haven't seen anyone reporting this particular version of the issue, so here goes:

On this DS1104Z-S (00.04.01.SP2/0.1.1), using a 10MHz square wave from the internal sig gen, I see jitter at 5us, but it's very slight, it's about 800ps vs. 400ps at 0us. I tried different signals and frequencies, and I don't see any correlation between rise time and jitter amount.

AC Trigger issue is there. Wouldn't know what to use AC triggering for though :)

Triggering on both flanks issue: I get the same behaviour with some choices of hold-off, even at values that are smaller than half a period. I'm getting the impression that the real holf-off time has some dead time added to it. Changing the value a bit quickly gets a proper eye pattern on screen in all trigger modes though.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 17, 2014, 04:02:59 pm
Ok,  so this only seams to be a problem if your DC coupling and have a DC offset and you don't want to have to adjust the trigger point when the offset changes.   It also occurs if you for some reason want to AC couple and AC trigger at the same time..not sure why. 

In the end this would impact a very small percentage of users and in many cases can be worked around. 

Has anyone tried using the External trigger in DC coupled mode yet with just a basic input cap to make it in effect AC coupled ?

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 17, 2014, 04:24:27 pm
Ok,  to follow up on my own suggestion I tried using the external trigger on my DS2000A with a capacitor input on the trigger to effectively AC couple the trigger.  Works like a charm.   Granted this is hardly optimal..it might be an option for some however that need that AC coupled trigger.   Interestingly it appears the external trigger is always DC coupled,  changing it to AC doesn't seam to have any effect.   My little capacitor trick gets around that as well.

Just my two cents.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 17, 2014, 04:57:53 pm
Why the user should be doing this. The fact that the issue has been known for two years and Rigol did not bother fixing it and even not removed/hide that option in the menu to me is a indication that Rigol is still a Mickey Mouse company. If i have a instrument on my bench i want to use it and trust it, not fight with it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 17, 2014, 05:06:06 pm
Why the user should be doing this. The fact that the issue has been known for two years and Rigol did not bother fixing it and even not removed/hide that option in the menu to me is a indication that Rigol is still a Mickey Mouse company. If i have a instrument on my bench i want to use it and trust it, not fight with it.

Just my personal Opinion here,  but it seams the Chinese companies can produce some really good hardware at times,  their software in many cases just seams to be lacking.   I think Rigol is the better of the bunch in that area.   I've seen so many other cases of a great Chinese product crippled by their firmware (software).   The English speaking based companies seam to do a bit better job with the firmware.   Rigol should hire a bunch of Russians to write all their code,  that's one group that can make make next to nothing do just about anything. 

Just my opinion.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fungus on November 17, 2014, 05:12:50 pm
The Rigol firmware seems pretty good to me.

I'm not saying the user interface can't be improved (especially the use of the multi-function knob!!) but there's some complex code in there and it seems to hang together quite well.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tinhead on November 17, 2014, 05:19:25 pm
Hello everyone.  I am not sure if you saw the Rigol response back.  If not here it is:

https://www.tequipment.net/assets/1/7/EEVBlog_message1.pdf (https://www.tequipment.net/assets/1/7/EEVBlog_message1.pdf)


and wtf is inside? a survey link from dumb MBA ...

let's answer some of these stupid questions, coming from an "Director of Product Marketing & SW Applications". Ohhh yeah.

- How often do you use AC coupling on your scope?

every fucking day

- When you use AC coupling on a channel, why do you do it?

not your fucking business, and btw, wtf you mean with this question?

So you trying to tell me that next time when i buy car i will get no reverse gear when i aswer in survey "i never use reverse gear" I paid for function introduced in datasheet/user manual/product description and you guys asking such stupid questions? Fix that shit in the fw or replace broken mainbaords, and stop asking such stupid things. Every other manufacturer (and even half of the cheap DIY china scopes) is capable of implementing AC coupled trigger/channel, so where is the problem for Rigol? This is very basic function, when you don't know this (and yeah, can you please remove all these shitty "skils" from your LinkedIn profile? this is pain in the ass, you have no idea about most of them, so please, remove them), then i think you should really think about new job. You worked before for Keithley and now Rigol and you have no idea about such simple things?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 17, 2014, 05:20:11 pm
Why the user should be doing these tricks and workarounds  The fact that the issue has been known for two years and Rigol did not bother fixing it and even not removed that option in the menu to me is a indication that Rigol is still a Mickey Mouse company. If i have a instrument on my bench i want to use it and trust it, not fight with it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fungus on November 17, 2014, 06:01:31 pm
So you trying to tell me that next time when i buy car i will get no reverse gear when i aswer in survey "i never use reverse gear" I paid for function introduced in datasheet/user manual/product description and you guys asking such stupid questions?

Bad analogy. It's not as fundamentally broken as "no reverse gear".

It's more like "the number plate light isn't as bright as I normally like it".


Fix that shit in the fw or replace broken mainbaords, and stop asking such stupid things. Every other manufacturer (and even half of the cheap DIY china scopes) is capable of implementing AC coupled trigger/channel, so where is the problem for Rigol?

Rigol is making 4-channel, 100MHz 'scopes and selling them for $400.

Your rant just sounds like you bought a half price horse and are complaining about the teeth. I'm sure most countries have a saying about that.


Rigol is still a Mickey Mouse company. If i have a instrument on my bench i want to use it and trust it, not fight with it.

Feel free to spend a lot more money...it's your perogative.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 17, 2014, 06:08:35 pm
Feel free to spend a lot more money...it's your perogative.

I spent $3900 on a 4000 series, been fighting with Rigol for almost a year to get issues fixed, they don't care.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fungus on November 17, 2014, 06:14:59 pm
Feel free to spend a lot more money...it's your perogative.

I spent $3900 on a 4000 series, been fighting with Rigol for almost a year to get issues fixed, they don't care.

Hmmm. OK, that's not so good. They should look after their $4000 customers...

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tinhead on November 17, 2014, 06:15:50 pm
Rigol is making 4-channel, 100MHz 'scopes and selling them for $400.

Your rant just sounds like you bought a half price horse and are complaining about the teeth. I'm sure most countries have a saying about that.

there must be something wrong with you:

1- in lot of countries one have to give lot of blowjobs to earn $400 (and cheap does not means bad or broken)
2- fully loaded DS2000A costs nearly $4000, and it does have same shit bug (that should be enought to care, right?)

Rant? how can an serious manufacturer ask such stupid questions? (except Q3, i have no idea why ppl are complained about, on TEK this was never ever working and nobody was crying about, it does not even make any sense to be implemented. But Q1 and Q2 are "US of Idiocracy-like" questions, from an MBA with RF and Electronic my ass skills, there is no hope for the human race).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wraper on November 17, 2014, 06:46:04 pm
Feel free to spend a lot more money...it's your perogative.

I spent $3900 on a 4000 series, been fighting with Rigol for almost a year to get issues fixed, they don't care.
In such situations I do very simple. Disassemble device in a way it cannot be noticed. It might be tricky to remove Rigol sticker but I've done that because of the crappy service when they refuse to admit an obvious fault. Then kill an electronics. Have done that by destroying particular IC or just changing some resistor value so I can simply fix back if something goes wrong. In Rigol case to not remove security sticker, might just stick wire inside and apply some voltage without disassembly at all. Bring them completely malfunctioning device  :-DD. Don't feel any remorse as this is not your fault that somebody is a jerk, and you just made things to be done as they should be in the first place.  8)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 17, 2014, 07:12:23 pm
In such situations I do very simple.

I know many people do such a thing and feel justified because they feel screwed or whatever.  My personal belief, right or wrong, is to just be honest.

When I retired from the mega corporation to work self employed, I thought I could easily ignore minor nuances and benefit from the value Rigol provides.  Well, lets just way, boy did I underestimate the nuances!    |O

Anyhow, I've learned my lesson with Rigol.  With companies like Hameg and Agilent  (and probably Tek, just don't have a bunch of personal experience with them), when you have a legitimate issue, it gets resolved in adequate time.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wraper on November 17, 2014, 07:19:10 pm
My personal belief, right or wrong, is to just be honest.
I'm honest on the first try. So I'm honest until another party is honest too.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jnissen on November 17, 2014, 08:11:11 pm

I'm honest on the first try. So I'm honest until another party is honest too.

Honesty and morals don't take a day off. Just because someone else or some company decides to lie and deceive never is an excuse to do the same.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wraper on November 17, 2014, 08:23:44 pm

I'm honest on the first try. So I'm honest until another party is honest too.

Honesty and morals don't take a day off. Just because someone else or some company decides to lie and deceive never is an excuse to do the same.
If nobody was going to repair faulty PCB anyway as it often happens nowadays, this does not change anything for another party. PCB was faulty, it just became more faulty so they cannot get away one more time. This is much more honest rather than overclocking computer hardware to the hell and then request warranty. Or destroying mobile phone firmware by flashing modded one and requesting warranty too.
I'm not in US, you know, where usually you get replacement without questions, even if there was no fault at all. Funny thing that you pay 1.5x US price and must prove that you are not elephant when device breaks.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 17, 2014, 08:45:45 pm
- How often do you use AC coupling on your scope?

every fucking day

This basically sums it up for me.  Most of the oscilloscopes I use (old ones) support peak-to-peak or auto level triggering so they do not need AC coupled triggering although most support both.  The ones which lack peak-to-peak and auto level triggering default to AC coupled triggering which is almost as good and sometimes better.  DC coupled triggering is needed at low input frequencies and for single shot and sometimes normal timebase mode so you always need to have it available.

If someone has never used an oscilloscope with peak-to-peak or auto level triggering, I could see not missing them but I consider one of these to be a must have feature since before 1970.  I did not realize the Rigols lacked both until now but this just makes AC coupled triggering more important.  Can you get by without it?  Sure, but it makes the oscilloscope more difficult to use.

Quote
- When you use AC coupling on a channel, why do you do it?

not your fucking business, and btw, wtf you mean with this question?

So I do not have to mess with the trigger level when probing different signals and using different offsets.

So you trying to tell me that next time when i buy car i will get no reverse gear when i aswer in survey "i never use reverse gear" I paid for function introduced in datasheet/user manual/product description and you guys asking such stupid questions?

Bad analogy. It's not as fundamentally broken as "no reverse gear".

It's more like "the number plate light isn't as bright as I normally like it".

I think tinhead's analogy is pretty good.  How often do you use reverse gear?  You can always park where you do not need reverse or get out and push your car backwards.

What occurred  to me was the Pentium FDIV bug as related by Bob Colwell (chief IA-32 architect on the Pentium Pro, Pentium II, Pentium III, and Pentium 4) where someone asked Andy Grove if he would accept a new car with has a big scratch on the driver's door.  The gas mileage is the same and the cargo capacity is the same and the radio still works so what is not to like?  Are you going to take it home?  Hell no!  You fix that because I paid for a car in perfect condition.

Public: I paid for a fully working chip, so give me one.
Intel: Nothing is bug-free, this bug doesn't affect you.
Public: I will judge the severity.  I won't trust you to do it.
Intel: We've always done it before.  You can't anyhow.
Public: Stand behind your brand or suffer the consequences.
Intel: Ok.  We give up.  Recall.  $475M (ouch!)

I am inclined to think Rigol cannot solve the AC coupled triggering bug since it has been going on for 2 years in the DS2000A series and the 5us jitter bug seems like it would be even more intractable.  Maybe they have their top men working on it.  Who?  Top ... men.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 17, 2014, 08:58:11 pm
I don't get why the LF Reject improves the stability of the Jitter,   LF Reject removes the lower frequencies (< ~20khz?).   This negates IMO any concept that it's a sample rate issue or such.   It's almost like some stray signal is getting in to the trigger circuit or perhaps a DC offset on some op-amp or something.  IDK.   It's just weird.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 17, 2014, 09:14:40 pm
I don't get why the LF Reject improves the stability of the Jitter,   LF Reject removes the lower frequencies (< ~20khz?).   This negates IMO any concept that it's a sample rate issue or such.   It's almost like some stray signal is getting in to the trigger circuit or perhaps a DC offset on some op-amp or something.  IDK.   It's just weird.

AC trigger coupling is just low frequency reject with a lower cutoff frequency so it works below 50/60 Hz.  With such a low cutoff frequency, if the filter (DSP in the FPGA?) is reset after every trigger, then it may not have enough time to settle before the new trigger occurs.  The low frequency reject trigger settles much more quickly.

You can sometimes see this happen on analog oscilloscopes which support both; in AC coupled trigger mode, the trigger position will initially visibly shift horizontally while in low frequency rejection mode, it settles much faster.  A 30 Hz low frequency cutoff has a time constant of 11.7 milliseconds while a 30 kHz low frequency cutoff has a time constant of 11.7 microseconds.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 17, 2014, 09:23:51 pm
I don't get why the LF Reject improves the stability of the Jitter,   LF Reject removes the lower frequencies (< ~20khz?).   This negates IMO any concept that it's a sample rate issue or such.   It's almost like some stray signal is getting in to the trigger circuit or perhaps a DC offset on some op-amp or something.  IDK.   It's just weird.

AC trigger coupling is just low frequency reject with a lower cutoff frequency so it works below 50/60 Hz.  With such a low cutoff frequency, if the filter (DSP in the FPGA?) is reset after every trigger, then it may not have enough time to settle before the new trigger occurs.  The low frequency reject trigger settles much more quickly.

You can sometimes see this happen on analog oscilloscopes which support both; in AC coupled trigger mode, the trigger position will initially visibly shift horizontally while in low frequency rejection mode, it settles much faster.  A 30 Hz low frequency cutoff has a time constant of 11.7 milliseconds while a 30 kHz low frequency cutoff has a time constant of 11.7 microseconds.

I have a 2465B in mint condition.  Has the same LF and HF rejects.  I was under the impression the LF reject removed low frequencies from the trigger path while HF Reject did the opposite (i.e. removed high frequencies).    So still it seams odd the LF Reject stabilizes the jutter to a degree while the HF Reject does not.   Makes me think their is a low freq element that's impacting things a bit.  Naturally my Tek doesn't suffer from these issues with the same signals.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 17, 2014, 10:52:39 pm
So, it seems the sample clock *is* spread.  Maybe not on purpose?   It's difficult to unwind if you're trying to get a decent FFT out of the thing.

Below are a couple shots from an SA looking at the ADC (HMCAD1511) CLKP and CLKN inputs with a differential probe.  These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").

I'm noting that the synthesizer output has discrete jumps of 100kHz.  Now where have we seen that number before??

The 5us jitter is pretty bad on this unit.

Still trying to glue all the observations together, but thought I'd post since it's interesting.

ADC:  http://www.hittite.com/products/view.html/view/HMCAD1511 (http://www.hittite.com/products/view.html/view/HMCAD1511)
Synth: http://www.analog.com/en/rfif-components/pll-synthesizersvcos/adf4360-7/products/product.html (http://www.analog.com/en/rfif-components/pll-synthesizersvcos/adf4360-7/products/product.html)

(Pardon the screen photos - my screen capture utility is not working...)

Edit:  firmware 4.02.SP3, board vers 0.1.1
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 17, 2014, 11:07:25 pm
AC trigger coupling is just low frequency reject with a lower cutoff frequency so it works below 50/60 Hz.  With such a low cutoff frequency, if the filter (DSP in the FPGA?) is reset after every trigger, then it may not have enough time to settle before the new trigger occurs.  The low frequency reject trigger settles much more quickly.

You can sometimes see this happen on analog oscilloscopes which support both; in AC coupled trigger mode, the trigger position will initially visibly shift horizontally while in low frequency rejection mode, it settles much faster.  A 30 Hz low frequency cutoff has a time constant of 11.7 milliseconds while a 30 kHz low frequency cutoff has a time constant of 11.7 microseconds.

I have a 2465B in mint condition.  Has the same LF and HF rejects.  I was under the impression the LF reject removed low frequencies from the trigger path while HF Reject did the opposite (i.e. removed high frequencies).    So still it seams odd the LF Reject stabilizes the jutter to a degree while the HF Reject does not.   Makes me think their is a low freq element that's impacting things a bit.  Naturally my Tek doesn't suffer from these issues with the same signals.

Low frequency reject is just another way to say high pass filter and high frequency reject is just another way to saw low pass filter.  The difference between AC coupling and low frequency reject is just the cutoff frequency.

Triggers work best on fast edges which will produce the lowest jitter but sometimes you want to deliberately ignore high frequencies or low frequencies.  For example triggering on the AC line will usually be improved with high frequency reject but if you want to trigger on a high frequency glitch which is on the AC line, low frequency reject would be appropriate.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 17, 2014, 11:10:11 pm


It's more like "the number plate light isn't as bright as I normally like it".




i like this.
and i would like to add that i wouldn't even remember it on every day of the week and the cops wouldn't notice it either!  :-DD

tinhead
Quote
Every other manufacturer (and even half of the cheap DIY china scopes) is capable of implementing AC coupled trigger/channel, so where is the problem for Rigol?

oh, come on!
i think we all read the examples where chinese scopes perform (or not) based on the serial number they have....and not in function that are rarely (if ever) used as this one.

with these bugs it's still best bang for the buck in market today.
or will you care to name something better in that price range?
it can have the same bugs as this one!
ehm...

d.hess
Quote
I think tinhead's analogy is pretty good.  How often do you use reverse gear?  You can always park where you do not need reverse or get out and push your car backwards.
no, it's not good beacuse it's not practical.
imagine sales of a car with reverse gear that is just awfuly noisy.
no, you can't compare even that with a function of a scope, because scopes today have many funcitons many people will rarely use.

most peopla here didn't know what ac trigger is, and that's a fact.
most car drivers know what is reverse and use it every day. it's the thing that prevents them from pushing the car.
otoh i doubt they know all the functions of ther new "entertainment systems" in cars....
this would be like missing an option to play...say....flv files in cars....or an .avi with indeo4 if we wanna be really obscure...i mean most people don't know about these things, so their chances of objecting it are rather diminished.

if you object (ie tinhead) it that much, fix it yourself!
(ie the approach markl just did with trying to figure it out himself)
and then charge to all rigol users that want it fixed, but i predict you'll soon be out of business if you would rely just on that source of income!  :P

this is not to say rigol shouldn't fix it....but somehow i doubt  most will would be sending it away to  fix this problem, esp. if rigol wouldn't pay the return shipping too.
(i must admit that i dunno would i even change the firmware if it would be fixable in that way...i mean...would i lose the hack options by doing that?  :scared: )

to that extent was there ever such a case that electronics company did that, i mean to repair a big amount of units and pay for their shipping?

but i like it how rigol got our hopes up when they said to do self calibration.... heh...

i would say rigol should investigate this and explain it thoroughly, and explain possible fix scenarios....that would be enough from them...not a pdf with few questions...
if you just send it to them for repair, you won't learn anything about your scope!  ;D

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 17, 2014, 11:14:27 pm
AC trigger coupling is just low frequency reject with a lower cutoff frequency so it works below 50/60 Hz.  With such a low cutoff frequency, if the filter (DSP in the FPGA?) is reset after every trigger, then it may not have enough time to settle before the new trigger occurs.  The low frequency reject trigger settles much more quickly.

You can sometimes see this happen on analog oscilloscopes which support both; in AC coupled trigger mode, the trigger position will initially visibly shift horizontally while in low frequency rejection mode, it settles much faster.  A 30 Hz low frequency cutoff has a time constant of 11.7 milliseconds while a 30 kHz low frequency cutoff has a time constant of 11.7 microseconds.

I have a 2465B in mint condition.  Has the same LF and HF rejects.  I was under the impression the LF reject removed low frequencies from the trigger path while HF Reject did the opposite (i.e. removed high frequencies).    So still it seams odd the LF Reject stabilizes the jutter to a degree while the HF Reject does not.   Makes me think their is a low freq element that's impacting things a bit.  Naturally my Tek doesn't suffer from these issues with the same signals.

Low frequency reject is just another way to say high pass filter and high frequency reject is just another way to saw low pass filter.  The difference between AC coupling and low frequency reject is just the cutoff frequency.

Triggers work best on fast edges which will produce the lowest jitter but sometimes you want to deliberately ignore high frequencies or low frequencies.  For example triggering on the AC line will usually be improved with high frequency reject but if you want to trigger on a high frequency glitch which is on the AC line, low frequency reject would be appropriate.

I get all that,  I just wonder what additional low freq is getting adding in to the trigger circuit perhaps internally.   My 2465B doesn't have any issues with jitter on the same exact signal with the same cable, same impedance..etc..etc.  So I have to presume the 2000A I have is getting some other noise in the trigger circuit at some point.   I also notice the problem doesn't seam to exist on the External trigger,  at least on mine.  Then again I can't get it to AC trigger with the external connection without a cap inline.   

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 17, 2014, 11:27:21 pm
These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").


given that some users don't have the problem, would it be possible some units have different 25mhz (ie botched) crystals that "ring" in a peculiar way and thereby influence the synthesizer?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 17, 2014, 11:33:51 pm
So, it seems the sample clock *is* spread.  Maybe not on purpose?   It's difficult to unwind if you're trying to get a decent FFT out of the thing.

The limited resolution of the DSO's built in FFT function may not be able to see it.

Quote
Below are a couple shots from an SA looking at the ADC (HMCAD1511) CLKP and CLKN inputs with a differential probe.  These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").

I'm noting that the synthesizer output has discrete jumps of 100kHz.  Now where have we seen that number before??

As Adam Savage would say, "Well, there's your problem."

I do not see any configuration in the ADF4360-7 frequency synthesizer for generating a spread spectrum output.  Maybe the modulation is from the 25 MHz clock source.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 17, 2014, 11:41:13 pm
I had posted a while back that my DS2000A series was showing significantly less jitter between 14.7x Mhz and 14.9x Mhz.   I forget the exact numbers and I'm too lazy to go look at my post :)    I found it odd that it had a sweet spot. 

In any event might be something to look at mathematically. 

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 12:21:12 am
Quote
Below are a couple shots from an SA looking at the ADC (HMCAD1511) CLKP and CLKN inputs with a differential probe.  These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").

I'm noting that the synthesizer output has discrete jumps of 100kHz.  Now where have we seen that number before??

As Adam Savage would say, "Well, there's your problem."

I do not see any configuration in the ADF4360-7 frequency synthesizer for generating a spread spectrum output.  Maybe the modulation is from the 25 MHz clock source.
The 25MHz input is very pure.

I notice, however, the loop filter is external between CP and VTUNE (VTUNE is the VCO input).  There's a 100kHz tone on the VTUNE pin, but's hard to say what the origin could be.  Perhaps their filter design has a problem and it introduces some instability.

Given that people are seeing varying amounts of jitter at 5us, it seems unlikely it's intended (such as to reduce EMI as has been suggested).  Rather the difference is from varying amounts of ingress noise or loop instability from component differences.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 18, 2014, 12:33:29 am
I get all that,  I just wonder what additional low freq is getting adding in to the trigger circuit perhaps internally.   My 2465B doesn't have any issues with jitter on the same exact signal with the same cable, same impedance..etc..etc.  So I have to presume the 2000A I have is getting some other noise in the trigger circuit at some point.   I also notice the problem doesn't seam to exist on the External trigger,  at least on mine.  Then again I can't get it to AC trigger with the external connection without a cap inline.

Since the 1000Z and 2000A triggers are done digitally in the FPGA, I assume the AC trigger coupling code is just broken.

It is not entirely clear how the external trigger input works on the 2000A.  I assume it operates as an analog trigger with some simple signal conditioning and a comparator driving one of the FPGA digital inputs.  AC coupling, low frequency, and high frequency reject would need to be implemented with analog circuits then so if they left those out, then they are not going to be adding them with a firmware update.

Actually they must be doing something a little more sophisticated to get better timing resolution that the FPGA processing clock will provide.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 02:03:49 am

The 25MHz input is very pure.

What a horrible clock for an ADC.  The PLL is unlocked. Nowhere in the datasheet it says spread spectrum. Can you check the 4360's Lock pin?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 02:09:59 am

I'm not saying the user interface can't be improved

Deleting measurements please... Please change UI to delete measurements by the same left gray buttons they are activated.
 :rant:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 02:29:49 am

The 25MHz input is very pure.

What a horrible clock for an ADC.  The PLL is unlocked. Nowhere in the datasheet it says spread spectrum. Can you check the 4360's Lock pin?
That's the first thing I looked for.  There is no dedicated lock pin.  The MUXOUT pin can be selected to be Analog Lock, Digital Lock, Scaled RF, Scaled Ref, or a few other things.  Without going to the next level and decoding the SPI bus, I don't know what's selected on MUXOUT.  All I can say that is that it's a constant high and that unfortunately doesn't say anything.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 02:54:25 am
Yes it is multiplexed, I forget. Here is a proper output from a 4360-8. The 6.5 MHz spurs are the phase  frequency detector artifacts from a 19.44MHz reference clock.

EDIT: And I remember I got something looking like the pics you posted when my PLL was not locked, that is why it ringed me a bell. I believe (I forget details) it was a overdrive problem on the reference input, the p-p voltage from a single-ended CMOS oscillator was too high, I had to squeeze in a 2-resistor voltage divider on 4360's Ref Clk input. Try checking Ref clock amplitude against the PLL datasheet.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 03:08:27 am
That looks like a nice output.

So we don't have a lock pin, but we can look at the Charge Pump pin.  Below is what it's doing.  I would expect it to be more symmetric if it was locked.

If you have one there (and that wasn't an old picture), what does your CP pin look like?

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 03:21:38 am
EDIT: And I remember I got something looking like the pics you posted when my PLL was not locked, that is why it ringed me a bell. I believe (I forget details) it was a overdrive problem on the reference input, the p-p voltage from a single-ended CMOS oscillator was too high, I had to squeeze in a 2-resistor voltage divider on 4360's Ref Clk input. Try checking Ref clock amplitude against the PLL datasheet.
Ref clock has almost a full 3.3V swing.  It's AC coupled into the 4360, -0.3 to +3.0 on the Ref pin.  Avdd is 3.3V.  That would be ok if I'm reading the spec right.

Were you driving it beyond the rails that caused the problem?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 18, 2014, 03:22:31 am
Quote
Below are a couple shots from an SA looking at the ADC (HMCAD1511) CLKP and CLKN inputs with a differential probe.  These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").

I'm noting that the synthesizer output has discrete jumps of 100kHz.  Now where have we seen that number before??

As Adam Savage would say, "Well, there's your problem."

I do not see any configuration in the ADF4360-7 frequency synthesizer for generating a spread spectrum output.  Maybe the modulation is from the 25 MHz clock source.

The 25MHz input is very pure.

I notice, however, the loop filter is external between CP and VTUNE (VTUNE is the VCO input).  There's a 100kHz tone on the VTUNE pin, but's hard to say what the origin could be.  Perhaps their filter design has a problem and it introduces some instability.

Given that people are seeing varying amounts of jitter at 5us, it seems unlikely it's intended (such as to reduce EMI as has been suggested).  Rather the difference is from varying amounts of ingress noise or loop instability from component differences.

I forgot to mention that a 100 kHz FM modulation source would appear as sidebands at increments of 100 kHz.

I doubt spread spectrum modulation was intended and suggested that it might have been included accidentally through a purchasing mistake.  Some DSOs in the past used frequency modulation of the sample clock to prevent synchronous sampling but when they did this, they also compensated for it after sampling so it was transparent to the user.

That the problem is originating in the PLL clock multiplier makes sense if the reference is divided down to 100 kHz first by the R divider which is certainly possible.  Maybe the wrong parts got used in the loop filter.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jlmoon on November 18, 2014, 03:40:46 am
I have a 2202, and experience the jitter across the entire horizontal position.  AC triggering, it  does not matter what position in relation to 0 center point ,  I have also noticed if you step up the memory depth to the higher levels the scope exhibits  some pretty interesting changes to the almost synced jitter.  I can also vary the input and make the jitter synchronize  with my input to make the waveform almost sync or stand still.


my 2c worth
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 18, 2014, 04:12:48 am
This scope has some rock solid jitter. This is with no AC coupling... perhaps Rigol will accept an RMA??

You can make your own sad charts with the attached Python script...  :(
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 04:55:45 am
If you have one there (and that wasn't an old picture), what does your CP pin look like?

I do not have the board handy, I need  to look for it. But if to do some math, on my screenshot the PFD spurs are at roughly 62dBc, and the carrier is at 0dBm, that is power, converting to voltage is 0.5mV p-p spurs on the PLL output. I am not sure how much leakage from PFD to RF Out is specified for the part but would probably not be anywhere close to the ones on the screenshots you captured.

Looking at your screenshots it is hard to estimate power in a 100kHz bin , but lets say judging by the envelope about -30dBm   which is after conversion to voltage is 20mV p-p. You measured 50mV p-p but as I said it was a rough estimate and the loop filter leakage may be attenuating the ripple on the loop filter pins.

I am falling sick at the moment, hope my calc made sense.

we can post a question on AD forum if your waveform makes sense to them , their engineers are pretty responsive.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 05:15:48 am
That looks like a nice output.

ADF4360 would not the best PLL, I did not like the spurs, that is why the proto board was shelved.
Look at what one can get from the Linear's LTC6946

Be-e-e-a-a-u-u-ty
 :-+

Note the center frequency. This is what I call a home brewed clock oscillator ...
And by the way it was referenced from a 10MHz Ovenized CXO. Rock solid, man. I had to use a prescaler to get the frequency down to measure on my trusty HP counter referenced from my Rubidium standard.
Oh man, sex on a stick
 :-+


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on November 18, 2014, 11:42:53 am
the DS1054Z arrived today.

One more data point:
Software version: 00.04.02.SP3
Board version: 0.1.1

Got teh jitters.
But also got >100MHz bandwidth too after applying some codes.


What a sensational DSO for the up and coming EE kids who are playing with Arduino/R-Pi/Pics/etc/etc
and inventing a new world as fast as they can!

And what is your sinewave  quality (specifications)  in picture 1 and 2.
Do you know how much it have jitter measured over 5us time period.

here is the DS1054Z of mine with the same 20Mhz sin from the fun gen at different delays.
0,5,20,25,30,100 us.
At 5 and 25 us delay, the jitter is clear to see. Nice signal out to 100us.

Test conditions:
Rigol DG1022 fun gen, via decent coax cable, 50 ohm terminated into ch1 of DS1054Z


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 03:02:58 pm
Hello everyone.  I am not sure if you saw the Rigol response back.  If not here it is:

https://www.tequipment.net/assets/1/7/EEVBlog_message1.pdf (https://www.tequipment.net/assets/1/7/EEVBlog_message1.pdf)

Thanks
Evan Cirelli

TEquipment.NET
Evan, at this point the 5us jitter is clearly not a trigger problem as concluded by Rigol in their letter.  And it also follows that their conclusion that it can be fixed in software is also not valid.  Even though they didn't see it, there are too many people seeing it now for them to hide from it, and it has nothing to do with self-cal or warm up.

It's possible that the problem could be fixed in software by loading different values into the ADF4360-7 PLL, but it could be also be a hardware problem with their loop filter design.

It's time to for Rigol weigh in on this with a real action plan.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 03:50:09 pm
So what would be a big deal to ask 2-3 people whose scopes have problems with jittef to ship them to Rigol for testing and reimburse shipping cost to those people. How much money would Rigol spend on shipping, $100 alltogether may be?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 18, 2014, 03:52:35 pm
So what would be a big deal to ask 2-3 people whose scopes have problems with jittef to ship them to Rigol for testing and reimburse shipping cost to those people. How much money would Rigol spend on shipping, $100 alltogether may be?

The odds of Rigol not having either scopes in house already or access to scopes with this issue are slim to none.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alank2 on November 18, 2014, 04:03:51 pm
Do we have a summary yet of which scope models are affected by which issues?

You guys are talking about a specific PLL - which models have this?

I think it would make sense to identify each issue specifically.  Is the 5uS jitter where it gets bad, then better, then bad, then better at 5uS intervals a DS1000Z only issue or is that specific issue also present in the DS2K and/or DS4K?  On my DS4K I didn't see it get bad then better then bad then better, but it wasn't as good when the trigger is off screen, making that a separate type of issue.  I will take a look at my DS2K in a bit.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jlmoon on November 18, 2014, 04:10:12 pm
Do we have a summary yet of which scope models are affected by which issues?

You guys are talking about a specific PLL - which models have this?

I think it would make sense to identify each issue specifically.  Is the 5uS jitter where it gets bad, then better, then bad, then better at 5uS intervals a DS1000Z only issue or is that specific issue also present in the DS2K and/or DS4K?  On my DS4K I didn't see it get bad then better then bad then better, but it wasn't as good when the trigger is off screen, making that a separate type of issue.  I will take a look at my DS2K in a bit.

On my DS2202 (non A version) it did not make any difference where the trigger point was set.  I could pan from one area to the next still experiencing the same jitter.  When I switched to DC coupled trigger waveforms cleaned up as they should.  I did notice that as I went lower in frequency < 1Mhz the jitter was not as noticeable as when I raised the frequency towards 20Mhz.  I did not get to try anything higher than 20Mhz, but will later.
 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pa3bca on November 18, 2014, 04:10:23 pm
Just another one for the stats: My DS1074Z (thinking it is an 1104Z) that I bought abt 6 months ago does not have the N x 5us jitter problem at all.
It does have (as expected) the AC trigger coupling issue (as does my 2072A) but that is a long known bug. I never use AC trigger coupling so it does not bother me.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 04:32:13 pm
So what would be a big deal to ask 2-3 people whose scopes have problems with jittef to ship them to Rigol for testing and reimburse shipping cost to those people. How much money would Rigol spend on shipping, $100 alltogether may be?
If I was Rigol, that's what I would do since they claim they haven't seen the issue.  That's why I was asking them for an action plan.

Mine is still in the 30-day eval period.  If the distributor or Rigol wants to send me a replacement unit, they can have this one to hack apart.

Do we have a summary yet of which scope models are affected by which issues?

You guys are talking about a specific PLL - which models have this?

I think it would make sense to identify each issue specifically.  Is the 5uS jitter where it gets bad, then better, then bad, then better at 5uS intervals a DS1000Z only issue or is that specific issue also present in the DS2K and/or DS4K?  On my DS4K I didn't see it get bad then better then bad then better, but it wasn't as good when the trigger is off screen, making that a separate type of issue.  I will take a look at my DS2K in a bit.

Sorry if that info got dropped... The one I've been testing with the 5us jitter issue is a DS1054Z, just arrived yesterday so it's factory fresh.  And yes, that's an accurate description of the problem.

A scan back through the thread should identify which other models have the 5us jitter problem.  There are several posts of screen captures at 5us delay intervals which is proof positive.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 18, 2014, 04:35:50 pm
I would be absolutely shocked if they truly can't reproduce the issue.  They are either still investigating, or unwilling to admit to duplication in fear of being forced to accept responsibility.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 05:04:43 pm
These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").

Is it CETECJ by any chance? Seems there is a manufacturer with this name, possibly in China. There seems nothing special in their oscillators, seems to be a cheap commodity product, so the PLL ripple is not caused by modation of the reference clock. Then if modulation is intentional, it could only be caused by reprogramming the PLL. Can you check for SPI activity on the PLL ? No need for decoding, just to see if the chip is getting written within that 100kHz cycle. Which i still doubt, since the PLL datasheet specifies frequency lock time is 400uS.

EDIT: may also check the power supply pins on the PLL for that modulation pattern
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 05:28:05 pm
These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").

Is it CETECJ by any chance? Seems there is a manufacturer with this name, possibly in China. There seems nothing special in their oscillators, seems to be a cheap commodity product, so the PLL ripple is not caused by modation of the reference clock. Then if modulation is intentional, it could only be caused by reprogramming the PLL. Can you check for SPI activity on the PLL ? No need for decoding, just to see if the chip is getting written within that 100kHz cycle. Which i still doubt, since the PLL datasheet specifies frequency lock time is 400uS.

EDIT: may also check the power supply pins on the PLL for that modulation pattern
Just double-checked - it is "CETDCJ".

I thought that too about it being reprogrammed.  All the SPI-related inputs are quiescent.  I can't find any indication of external 100kHz influences.

I've also been around to all the power supply pins looking for 100kHz with a scope.  I'll have a look with the SA if the chip is overly sensitive to that.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: bitbanger on November 18, 2014, 06:18:04 pm
^ I was about to post last night because it hasn't been mentioned, but my 1074Z is (as you would assume) affected similarly.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 18, 2014, 07:23:26 pm
I thought that too about it being reprogrammed.  All the SPI-related inputs are quiescent.  I can't find any indication of external 100kHz influences.

I've also been around to all the power supply pins looking for 100kHz with a scope.  I'll have a look with the SA if the chip is overly sensitive to that.

This makes me hope that it's an FPGA problem and not in the PLL. I won't RMA this until we know, but it's probably the ADF4360-7 based on the variations people are seeing.

A sufficiently clever FPGA guru could calibrate this one out in a few hours.  How many gates are left in that Xilinx?? ;D
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 07:43:42 pm
EDIT: may also check the power supply pins on the PLL for that modulation pattern
...
I've also been around to all the power supply pins looking for 100kHz with a scope.  I'll have a look with the SA if the chip is overly sensitive to that.
Ok, according to the SA, all PSP pins are <6mVpp for both 1GHz and 100kHz, except the internal compensation node, Cc.

Cc has a stronger 1GHz component of ~63mVpp.  Since that's an internal node there's not much documentation for it so that might be normal.  There's a decoupling cap on it to ground and the spec says it should be 10nF.  I'm measuring it as 1nF, but that's in-circuit so my reading might be off (but likely not that much).  Squeezing a 100nF next to it with a tweezers (I didn't have a 0402 10nF) doesn't affect anything anyway.

I don't think there's much more I'm going to do with it at this point until we hear from Rigol.  To be fair to them and let them support customers their way, I've also opened up a case through their web site and I've referenced this thread.  If I get anything towards a resolution that didn't also make it here, I'll post back.

I'm just pursuing the 5us jitter problem in the case.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 08:46:04 pm
Thank you MarkL for the efforts. So to summarize we think the ADC clock source ADF4360-7 PLL does not operate as it should , i.e it is unable to phase lock to its 25MHz external reference. Possibly may be caused by deficiencies in the PLL loop design or PLL registers programming.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 18, 2014, 09:14:18 pm
Thank you MarkL for the efforts. So to summarize we think the ADC clock source ADF4360-7 PLL does not operate as it should , i.e it is unable to phase lock to its 25MHz external reference. Possibly may be caused by deficiencies in the PLL loop design or PLL registers programming.
Yep - I think that sums it up accurately.  And thanks for your help.  It was nice finding someone who's actually worked with this chip.

And that LTC6946 is very impressive! Guess where I'm going to look first for my next PLL design...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 18, 2014, 09:15:40 pm
Wonder if that same chip is used in the 4000s?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 18, 2014, 11:04:22 pm
Here are Dave's DS2000Z & DS1000Z teardown images of the AD PLL. Looks like there are lots more caps on the DS2000Z...

I like to think that Dave's criticism of Rigol lasering the chips made them stop... which said to us "we took the time away from testing the vendor's PPL filter to just laser off the label".

I'm blown away by the quality and price point of this scope. If only they'd fix this they'd corner the market on cheap oscilloscopes.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 18, 2014, 11:22:46 pm
Thanks for the pics. Lasering the pll chip was totally unnecessary, anyone who used ADF4360 before would instantly recognize it

 :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jmc2000 on November 19, 2014, 12:29:11 am
Thanks for the pics. Lasering the pll chip was totally unnecessary, anyone who used ADF4360 before would instantly recognize it

 :)

Is it possible that the PLL chip is being stretched beyond its spec which is why it was lasered, just like the ADCs in the early Rigols?

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 19, 2014, 01:05:22 am
Hopefully it was not because they used knock-off chips
 8)

In the meanwhile, if someone who has a DS1000/2000 series scope that does NOT have 5uS jitter could check the ADF4360 PLL output with a spectrum analyzer (1 or2 GHz) , or just use any low frequency scope to check PLL pin 7 (loop filter ) and compare with what MarkL posted on page 19 and 20 of this thread, that would be great.

If Dave still reads this thread and could do a quick check that would be nice

EDIT: not pin 7, pin 24
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 19, 2014, 01:15:22 am
My test setup was using a Hp 3325 function generator at close to 20 Mhz.  Roughly 5 volts input using x1 (bnc cable) in X1 mode on scope.  Has anyone noticed what happens when you raise the memory depth from the lower values towards 56M points.  ?

Yes, that is normal, because at the bigger memory depths you get a much less wfps update speed.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 19, 2014, 03:16:20 am
Is it possible that the PLL chip is being stretched beyond its spec which is why it was lasered, just like the ADCs in the early Rigols?

I did not see anything in the specifications which would limit its use in this sort of application.  The phase noise when it is operating correctly is not limiting the performance of the DSO.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 19, 2014, 04:19:53 am
If I'm reading the Rigol manual correctly here's how out-of-spec the jitter is. My scope is essentially useless out +/- 1 us.

(http://i.imgur.com/EW8mG4M.png)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: XFDDesign on November 19, 2014, 04:31:48 am
Here are Dave's DS2000Z & DS1000Z teardown images of the AD PLL. Looks like there are lots more caps on the DS2000Z...

I like to think that Dave's criticism of Rigol lasering the chips made them stop... which said to us "we took the time away from testing the vendor's PPL filter to just laser off the label".

I'm blown away by the quality and price point of this scope. If only they'd fix this they'd corner the market on cheap oscilloscopes.

For what it's worth, they're missing the required 470ohm resistors in parallel with the tuning inductors in the picture.

That being said, what's the basis for determining this to be a PLL issue? Is the CP output showing something erratic which correlates to this jitter issue?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 19, 2014, 04:53:46 am
If I'm reading the Rigol manual correctly here's how out-of-spec the jitter is. My scope is essentially useless out +/- 1 us.

Timebase accuracy is not the same as jitter.  I was not able to find any sort of jitter specification in the user manual but it should be insignificant out to at least 500us.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on November 19, 2014, 05:10:31 am
I would be absolutely shocked if they truly can't reproduce the issue.  They are either still investigating, or unwilling to admit to duplication in fear of being forced to accept responsibility.

I'd say they want to have an answer (a no BS one) and solution at the same time. Coming in with both will help the sell product. I can't really blame them, confidence is a big word in the industry.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 19, 2014, 05:38:15 am
For what it's worth, they're missing the required 470ohm resistors in parallel with the tuning inductors in the picture.

That being said, what's the basis for determining this to be a PLL issue? Is the CP output showing something erratic which correlates to this jitter issue?

Per the Datasheet the 470 Ohm resistors required if the inductors are 3.3uH and above. For 1GHz clock the inductors would be smaller than that - see the inductors selection chart in the Datasheet.

The basis for determining the PLL is a suspect is it outputs wideband garbage instead of a single clock frequency into the downstream ADC - see page 19 of this thread. Also the CP pin shows 100kHz ripple which is 10uS period and that correlates to the 10uS jitter cycle in the chart Nonorthogonal posted  above.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: ulix on November 19, 2014, 02:48:05 pm
Hi everybody,

what I know is: Rigol does know the problem and they found it! There will statement/ update in the near future!
Please keep calm, they are doing their best  :-+
cheers
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: XFDDesign on November 19, 2014, 03:16:57 pm
Per the Datasheet the 470 Ohm resistors required if the inductors are 3.3uH and above. For 1GHz clock the inductors would be smaller than that - see the inductors selection chart in the Datasheet.

The basis for determining the PLL is a suspect is it outputs wideband garbage instead of a single clock frequency into the downstream ADC - see page 19 of this thread. Also the CP pin shows 100kHz ripple which is 10uS period and that correlates to the 10uS jitter cycle in the chart Nonorthogonal posted  above.

Fair enough on the <=3.3nH inductors. The trim I've used has always been larger values.

So, it seems the sample clock *is* spread.  Maybe not on purpose?   It's difficult to unwind if you're trying to get a decent FFT out of the thing.

Below are a couple shots from an SA looking at the ADC (HMCAD1511) CLKP and CLKN inputs with a differential probe.  These inputs are being generated by an ADF4360-7 frequency synthesizer, which has as its base clock a 25MHz crystal/resonator/oscillator block (not sure exactly, marked "CETDCJ 25.000").

I'm noting that the synthesizer output has discrete jumps of 100kHz.  Now where have we seen that number before??

The 5us jitter is pretty bad on this unit.

Still trying to glue all the observations together, but thought I'd post since it's interesting.

(Pardon the screen photos - my screen capture utility is not working...)

Edit:  firmware 4.02.SP3, board vers 0.1.1

Does this "spreading" go away with 0-delay on AC (trigger) coupling? Is there any chance you could measure the passives used for the charge-pump output filter? Looking at page 19 of this thread, they're using the part for a fixed 1.0GHz which I hadn't caught. As long as that's fixed, something else is up. Has anyone determined if the MUXOUT pin is being used? If not, it could be hacked to drive the Open-drain form of Lock-detect. The thing that still has me wondering is "how much" is the amplitude of this 100kHz? Why would this not be an issue with DC coupled mode? I might suggest redesigning the loop filter, but before that, I would probe the Latch Enable pin to see if it's being subject to multiple writes. If it is, that might be where the "spreading" is coming from and it might be DSS.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 19, 2014, 03:42:39 pm
Does this "spreading" go away with 0-delay on AC (trigger) coupling?

No and it has nothing to do with AC trigger coupling.  Triggering occurs after the signal is digitized so an unstable sampling clock is irrelevant.  It shows up when the acquisition is delayed from the trigger point or with a long record length where you can see significantly before or after the trigger point.

The same thing happens when an oscilloscope triggers on an edge which occurs at an irregular interval.  The jitter from edge to edge is not seen unless the acquisition is long enough to catch more than one.

Quote
Why would this not be an issue with DC coupled mode?

It is an issue with DC coupled triggering.  AC coupled triggering has an unrelated serious problem.

Quote
I might suggest redesigning the loop filter, but before that, I would probe the Latch Enable pin to see if it's being subject to multiple writes. If it is, that might be where the "spreading" is coming from and it might be DSS.

MarkL reported that the SPI port is not being used while this is going on which is easy enough to check.  I assume the PLL is being initialized and then left alone.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: XFDDesign on November 19, 2014, 03:52:28 pm

It is an issue with DC coupled triggering.  AC coupled triggering has an unrelated serious problem.

MarkL reported that the SPI port is not being used while this is going on which is easy enough to check.  I assume the PLL is being initialized and then left alone.

I was under the impression that the whole of this discussion was a hunt to solve the AC trigger coupling oddity which shows jitter at 5,15,...us delay intervals. Has this now forked into multiple other issues?

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 19, 2014, 04:02:59 pm

It is an issue with DC coupled triggering.  AC coupled triggering has an unrelated serious problem.

MarkL reported that the SPI port is not being used while this is going on which is easy enough to check.  I assume the PLL is being initialized and then left alone.

I was under the impression that the whole of this discussion was a hunt to solve the AC trigger coupling oddity which shows jitter at 5,15,...us delay intervals. Has this now forked into multiple other issues?

Dave identified three problems in his video: AC trigger coupling, jitter at 5us and every 10us after that, and trigger holdoff interacting with dual edge triggering.

The AC triggering coupling problem is completely separate from jitter at 5us and every 10us after that.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 19, 2014, 05:13:54 pm
Hi everybody,

what I know is: Rigol does know the problem and they found it! There will statement/ update in the near future!
Please keep calm, they are doing their best  :-+
cheers

Sure they do after we pointed out it is the  4360 PLL.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 19, 2014, 05:24:03 pm
Quote from: XFDDesign link=topic=38902.msg553827#

 Has anyone determined if the MUXOUT pin is being used?

Looking at the board photos recently posted in this thread this pin is not connected to anything.

Quote
where the "spreading" is coming from and it might be DSS.

There is no DDS. The 4360 PLL is referenced from a 25MHz oscillator
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: XFDDesign on November 19, 2014, 06:23:06 pm

There is no DDS. The 4360 PLL is referenced from a 25MHz oscillator

DSS - Digital Spread Spectrum
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 19, 2014, 07:53:34 pm

So we don't have a lock pin, but we can look at the Charge Pump pin.  Below is what it's doing.  I would expect it to be more symmetric if it was locked.

If you have one there (and that wasn't an old picture), what does your CP pin look like?

I found my old proto board, this is what I have on the CP pin. The picture is scaled same as yours, 5uS/ and 10mV/.
There is no 100kHz or any other low frequency ripple whatsoever. The total noise includes noise from my on-board switching regulator and cross-coupled leak from the RF output.


EDIT: I re-posted your screenshot made on Agilent just for reader's convenience.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 19, 2014, 08:37:09 pm
I found my old proto board, this is what I have on the CP pin. The picture is scaled same as yours, 5uS/ and 10mV/.
There is no 100kHz or any other low frequency ripple whatsoever. The total noise includes noise from my on-board switching regulator and cross-coupled leak from the RF output.


EDIT: I re-posted your screenshot made on Agilent just for reader's convenience.
Ah, that looks more like I would expect.  Thanks for digging out your old board.  Are you still running it at 193MHz?

As I recall there was some RFout coupled into my CP pin also.  I did that capture in high-res mode, so it would have gotten filtered out.  What I'm not recalling was the magnitude of the RF.

For interest's sake, I'll grab a CP pin capture in normal mode.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 19, 2014, 09:34:57 pm
By dumping the 12M point memory and using a decent FFT this scope turns into a hobbyist-grade spectrum analyzer. I like. 8)

I'm guessing the PLL's harmonics are those huge spikes... among all the internal CPU clocks and what not.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 19, 2014, 09:42:48 pm
For interest's sake, I'll grab a CP pin capture in normal mode.
No real surprise.  There is some leakage, but it's not a crazy amount.  It looks to be higher than yours but that's probably because the higher frequency is coupling more.

Also below is an FFT of the same scope capture in the 1GHz region detailing the leakage.  Again, no surprises that I can see, except of course this shouldn't be happening.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 19, 2014, 09:50:16 pm
By dumping the 12M point memory and using a decent FFT this scope turns into a hobbyist-grade spectrum analyzer. I like. 8)

I'm guessing the PLL's harmonics are those huge spikes... among all the internal CPU clocks and what not.
If FFT is your goal, this PLL problem is really going to make a mess out of it.

Feed the scope a pure tone, zoom in on some of those plots, and you should see your carrier modulated at 100kHz (similar to the one I just posted).  And the FM deviation should vary from scope to scope because we see differences in the 5us jitter width.

Edit:  And actually, the sample clock isn't even being modulated by a sine wave.  It's a sawtooth with all of its lovely harmonics.  Should create some interesting artifacts.  Yummy.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 20, 2014, 12:04:30 am
MarkL,

Next time can you try a simple test - try to heat the 25MHz oscillator with hot air pencil or soldering gun , and cool with dust blower or a piece of metal cured in the freezer for a few min and watch the CP pin if it shows any sign of the PLL trying to lock, or if we are lucky it may even lock. That would indicate either the oscillator may be off of the spec frequency or the loop filter bandwidth may be too narrow. 

A better test would be to unsolder the DC blocking cap between the 25MHz oscillator and PLL and connect an external signal gen there (DC blocked) and vary the frequency slightly and see if the PLL locks. That is only if you willing to touch the board with solder.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: XFDDesign on November 20, 2014, 12:36:40 am
For interest's sake, I'll grab a CP pin capture in normal mode.
No real surprise.  There is some leakage, but it's not a crazy amount.  It looks to be higher than yours but that's probably because the higher frequency is coupling more.

Also below is an FFT of the same scope capture in the 1GHz region detailing the leakage.  Again, no surprises that I can see, except of course this shouldn't be happening.

Something bugs me about this: for a 1GHz center, there is no actual "carrier" but rather a band of noise. If this thing is actually clocking there should be a significant tone, at least 125mVrms in Amplitude (or about 40dB larger than the -60dBV you're measuring right now).

You're probing the CP pin, so I'm thinking looking at the 1GHz center isn't really a good metric, but rather the DC-200kHz range. Garbage coming out of the VCO will be proportional to the noise at VTune/CP by way of the Kv of the VCO. In simplifier terms, if you had 1uVrms of noise at 1kHz on a 12MHz/V VCO, you would expect your skirt to distort at around 12Hz from carrier. 10uVrms and it goes to 120Hz, etc. Have a band of noise, and then the skirt gets ugly, quickly.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 20, 2014, 12:51:48 am
UPDATE FROM RIGOL

Short and not explanatory, but:

Quote
1: We have reproduced the two issues in R&D side;
2: All issues can be fixed by firmware updating without deleting any feature;
3: The trail firmware form R&D will be released in early next week, that can be used for Dave or some urgent cases.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 20, 2014, 12:52:14 am
MarkL,

Next time can you try a simple test - try to heat the 25MHz oscillator with hot air pencil or soldering gun , and cool with dust blower or a piece of metal cured in the freezer for a few min and watch the CP pin if it shows any sign of the PLL trying to lock, or if we are lucky it may even lock. That would indicate either the oscillator may be off of the spec frequency or the loop filter bandwidth may be too narrow. 
Great suggestion - I tried it.

There is sensitivity to temperature.  The hotter it gets with an air pencil, the less deviation in the modulation.  The colder with freeze spray, the wider the deviation.  I was not able to get it hot enough to lock, but I didn't heat it beyond about 100C.

Quote
A better test would be to unsolder the DC blocking cap between the 25MHz oscillator and PLL and connect an external signal gen there (DC blocked) and vary the frequency slightly and see if the PLL locks. That is only if you willing to touch the board with solder.
If we were beyond the 30-day return window, I would go at it in an instant.

If this problem has no resolution within the return window, it's going back.  I've learned the lesson that what you see in front of you is what you're buying, especially with this lower end stuff.  I wouldn't blame Rigol in the least for not taking it back once the modding started.

That being said, I'm going to see if I can find a spec sheet for the oscillator on the off-chance that one of those pads is an output enable.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 20, 2014, 01:07:04 am
For interest's sake, I'll grab a CP pin capture in normal mode.
No real surprise.  There is some leakage, but it's not a crazy amount.  It looks to be higher than yours but that's probably because the higher frequency is coupling more.

Also below is an FFT of the same scope capture in the 1GHz region detailing the leakage.  Again, no surprises that I can see, except of course this shouldn't be happening.

Something bugs me about this: for a 1GHz center, there is no actual "carrier" but rather a band of noise. If this thing is actually clocking there should be a significant tone, at least 125mVrms in Amplitude (or about 40dB larger than the -60dBV you're measuring right now).

You're probing the CP pin, so I'm thinking looking at the 1GHz center isn't really a good metric, but rather the DC-200kHz range. Garbage coming out of the VCO will be proportional to the noise at VTune/CP by way of the Kv of the VCO. In simplifier terms, if you had 1uVrms of noise at 1kHz on a 12MHz/V VCO, you would expect your skirt to distort at around 12Hz from carrier. 10uVrms and it goes to 120Hz, etc. Have a band of noise, and then the skirt gets ugly, quickly.
You're right, 1GHz is not the frequency of interest in the loop filter.  The question was if there was any significant leakage from the RF out into the loop filter.  I was just making sure since I had the scope in high-res mode when making the previous measurement.

It was just a verification.  I thought it was interesting to include the FFT shot since measuring the leakage this way is more meaningful than eyeballing the fuzz in the scope screen shot.

But since there is a small amount of leakage, the 1GHz FFT of the leakage shows the same 100kHz modulation that was seen on the SA back on page 19.  The 100kHz signal is also in the FFT, but I didn't post it.  We can already see the 100kHz signal directly in the time domain.

Edit: Fix typo.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Monkeh on November 20, 2014, 01:10:11 am
UPDATE FROM RIGOL

Short and not explanatory, but:

Quote
1: We have reproduced the two issues in R&D side;
2: All issues can be fixed by firmware updating without deleting any feature;
3: The trail firmware form R&D will be released in early next week, that can be used for Dave or some urgent cases.

It would be greatly appreciated if they or you would post both the trial firmware and the previous full release version as open downloads instead of having to play the email game to get them.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 20, 2014, 01:11:58 am
Short and not explanatory, but:

Quote
1: We have reproduced the two issues in R&D side;
2: All issues can be fixed by firmware updating without deleting any feature;
3: The trail firmware form R&D will be released in early next week, that can be used for Dave or some urgent cases.
Ok, great.  Thanks for forwarding the info.

As a Rigol customer, I'm interested to see this echoed through my open case.

It's been a great discussion and investigation, but I hope every problem does not need the visibly of a 23 page, global pile-on to be addressed.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 20, 2014, 01:24:41 am
UPDATE FROM RIGOL

Without this Blog they would not bother

Quote
2: All issues can be fixed by firmware updating *without deleting any feature*

OK that is what we are hoping for

 8)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on November 20, 2014, 01:37:27 am
I get the impression shipping to dealers will continue as usual.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 20, 2014, 01:41:55 am
UPDATE FROM RIGOL

Without this Blog they would not bother
Well, if they want to play in the higher end market with their other gear, which is clearly their aim, they need to learn the customer support game.  I've recently had a couple of open cases with Agilent/Keysight and I don't wonder at all where my extra money goes buying their gear.

A major part of evaluating a vendor is taking their technical support for a spin.  That didn't really happen here.  Maybe another bug will come up... Nah!

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 20, 2014, 02:06:31 am
Maybe another bug will come up... Nah!

And they still have the third bug  to address, I am dying to learn which one out of the 3 reported it is.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 20, 2014, 02:14:59 am
Maybe another bug will come up... Nah!

And they still have the third bug  to address, I am dying to learn which one out of the 3 reported it is.
You have a point, but I'm assuming they're addressing the 5us jitter and the AC trigger coupling.

I thought the dual edge trigger "bug" was pilot error.  The same edge happened to be synchronized to the sweep timing and could be corrected by increasing the holdoff.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 20, 2014, 02:18:28 am
Maybe another bug will come up... Nah!

And they still have the third bug  to address, I am dying to learn which one out of the 3 reported it is.

1. Trigger jitter when using 5us horizontal offset
2. Trigger jitter when using AC trigger coupling.

Not sure what the third bug is? The "dual slope triggering not working bug" is not a bug at all, just correct behaviour of trigger holdoff: link to earlier in this thread (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg551012/#msg551012).

EDIT: MarkL, must have pressed "reply" at the same time! Great minds, right?  :)  :P
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 20, 2014, 02:30:24 am
EDIT: MarkL, must have pressed "reply" at the same time! Great minds, right?  :)  :P
Doesn't hurt to repeat, especially in this thread!

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 20, 2014, 02:45:43 am
I'm assuming they're addressing the 5us jitter and the AC trigger coupling.

I wonder if DS20xx AC trigger coupling will also be addressed, mine does not have the 5uS thing but does have that one.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fagear on November 20, 2014, 02:56:08 am
2. Trigger jitter when using AC trigger coupling.

Not sure what the third bug is?
There is actualy 4th one. I've showed it in my video (http://youtu.be/bVg-lpLwmKc?t=13m45s): on DS2000A with EXT source it works only with DC coupled trigger. Menu is the same (AC/DC/rejects), but it doesn't affect anything, EXT trigger always work with DC coupling.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: fusebit on November 20, 2014, 03:00:35 am
Despite the fact that this problem seems to be solved soon:
Yesterda my DS1074Z arrived, Software 00.04.00

I can't reproduce the 5us Jitter issue.

The AC trigger coupling is not relevant for me. Now I'll watch Dave's latest video to understand what it's about  ::)

Edit: Seen the video, now I'll check it out...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 20, 2014, 03:04:04 am
Well Rigol some time ago produced a kool paper signed by a sales rep that they have tested a few scopes from their stock and could not reproduce the problem. I guess you got one of those 'no-problem' units

 :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 20, 2014, 03:28:34 am
And they still have the third bug  to address, I am dying to learn which one out of the 3 reported it is.

There is no third bug, that was an unverified throw-away PEBKAC on my part.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 20, 2014, 03:34:01 am
And they still have the third bug  to address, I am dying to learn which one out of the 3 reported it is.

There is no third bug, that was an unverified throw-away PEBKAC on my part.

Just to keep us on our toes.  Gotcha. ;)

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 20, 2014, 03:35:09 am
2. Trigger jitter when using AC trigger coupling.

Not sure what the third bug is?
There is actualy 4th one. I've showed it in my video (http://youtu.be/bVg-lpLwmKc?t=13m45s): on DS2000A with EXT source it works only with DC coupled trigger. Menu is the same (AC/DC/rejects), but it doesn't affect anything, EXT trigger always work with DC coupling.

I suspect this bug only exists in the documentation and user interface with external triggering only supporting DC coupling because of the hardware.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 20, 2014, 06:04:13 am
The menu options to select AC coupling need to go away on the DS2000A when using the external trigger.  I've confirmed as well that it only supports DC coupling.  You can of course put a cap inline and now you have your AC coupling  :-\

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wlanfox on November 20, 2014, 07:40:22 am
Maybe another bug will come up... Nah!

And they still have the third bug  to address, I am dying to learn which one out of the 3 reported it is.

1. Trigger jitter when using 5us horizontal offset
2. Trigger jitter when using AC trigger coupling.

Not sure what the third bug is? The "dual slope triggering not working bug" is not a bug at all, just correct behaviour of trigger holdoff: link to earlier in this thread (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg551012/#msg551012).

EDIT: MarkL, must have pressed "reply" at the same time! Great minds, right?  :)  :P

I believe that third one still a bug. Including pictures, input signal is a 1 kHz square wave 50% duty cycle, the hold off is set to 100ns and only by changing the time base (nothing else) some times it will triggers on both falling/rising, notice didn't change anything else other then time base.

Scope Details:
MSO2202A, SW ver 00.03.01, HW ver 2.2
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 20, 2014, 08:06:15 am
I believe that third one still a bug. Including pictures, input signal is a 1 kHz square wave 50% duty cycle, the hold off is set to 100ns and only by changing the time base (nothing else) some times it will triggers on both falling/rising, notice didn't change anything else other then time base.

Scope Details:
MSO2202A, SW ver 00.03.01, HW ver 2.2

This is very, very interesting. For context, having the effective holdoff "change" as the timebase is manipulated is standard fare for analog oscilloscopes (or at least, the one analog I've played with). The reason is that the holdoff period doesn't start until the horizontal sweep is completed; which means that the distance between triggers is timebase + holdoff. So a change in behaviour due only to a timebase change is completely expected...

Except, in the video in my earlier post (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg551012/#msg551012), I demonstrated very explicitly that the Rigol DS2202 doesn't do this. The holdoff is measured from the trigger point, and the selected timebase has absolutely no bearing on the trigger behaviour -- down to the exact nanosecond value of holdoff that flips it between states. So it's extremely strange that your Rigol MSO2202A is behaving more like a Hitachi 20MHz Analog CRO than a Rigol DS2202.

To confirm exactly how it's behaving, could you please show the behaviour with the following 6 holdoff settings:

200us/div, holdoff = about 0.3ms (that's 300us, or 300k ns)
200us/div, holdoff = about 0.7ms
200us/div, holdoff = about 1ms
And the same three holdoffs, but with 500 us/div.

That way, we can see if it's just the timebase futzing with the holdoff settings, or something more broken.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: wlanfox on November 20, 2014, 08:25:53 am
I believe that third one still a bug. Including pictures, input signal is a 1 kHz square wave 50% duty cycle, the hold off is set to 100ns and only by changing the time base (nothing else) some times it will triggers on both falling/rising, notice didn't change anything else other then time base.

Scope Details:
MSO2202A, SW ver 00.03.01, HW ver 2.2

This is very, very interesting. For context, having the effective holdoff "change" as the timebase is manipulated is standard fare for analog oscilloscopes (or at least, the one analog I've played with). The reason is that the holdoff period doesn't start until the horizontal sweep is completed; which means that the distance between triggers is timebase + holdoff. So a change in behaviour due only to a timebase change is completely expected...

Except, in the video that I linked in my earlier post, I demonstrated very explicitly that the Rigol DS2202 doesn't do this. The holdoff is measured from the trigger point, and the selected timebase has absolutely no bearing on the trigger behaviour -- down to the exact nanosecond value of holdoff that flips it between states. So it's extremely strange that your Rigol MSO2202A is behaviour more like a Hitachi 20MHz Analog CRO than a Rigol DS2202.

To confirm exactly how it's behaving, could you please show the behaviour with the follow 6 settings:

200us/div, holdoff = about 0.3ms (that's 300us, or 300k ns)
200us/div, holdoff = about 0.7ms
200us/div, holdoff = about 1ms
And the same, but with 500 us/div.

That way, we can see if it's just the timebase futzing with the holdoff settings, or something more broken.

FYI I quickly tried on my old DS1052E, and it trigger just fine on both edges at 300us holdoff (and it kept trigger on both all the way from 500ns to 300us), I had tried it before to compare.

here they are:

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fagear on November 20, 2014, 09:18:01 am
I suspect this bug only exists in the documentation and user interface with external triggering only supporting DC coupling because of the hardware.
But it is still a bug. ;)
And I mentioned it in the video: Rigol either have to remove coupling settings for EXT input (due to hardware) or fix all items in the menu.
I don't know which way they designed trigger circuit, but if it is "purely digital" (as it is for analog channels) maybe they can implement "AC coupling" on EXT input as well.
And it will be nice if they'll add multiplier setting for the EXT input (0.0001x...1000x) as it is in the channel menu (for correct trigger voltage display).
DS4000 does AC coupling for EXT input as well as voltage multiplier auto sensing.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 20, 2014, 12:41:47 pm
here they are:

Very interesting, thank you for doing that. Something whacky is going on there because regardless of how holdoff is implemented (with respect to when the holdoff countdown begins), adding one full waveform period (1ms in this 1kHz case) to the holdoff setting should produce identical results. So your "1ms" results should look identical to the 100ns (let's call it 0ms) results from your earlier post. But they're backwards, reversed. However, on the other hand, changing holdoff is changing the behaviour, so it's close to right. Sort of. I don't suppose 0.95ms or 1.05ms produce different results? We might just be sitting on a noisy edge case. (Sorry, in hindsight the holdoffs I chose were... poorly chosen.) No need to upload screenshots, just report whether there's a change in behavious when moving +/- 0.05ms from 1ms holdoff.

I wish I could be there to try putting in different frequencies, figuring out exactly which holdoff values cause the waveform to transitions from locked/unlocked, inferring what the true trigger-to-trigger holdoff values are... sounds like a fun debugging job!

I suspect this bug only exists in the documentation and user interface with external triggering only supporting DC coupling because of the hardware.
But it is still a bug. ;)
And I mentioned it in the video: Rigol either have to remove coupling settings for EXT input (due to hardware) or fix all items in the menu.
I don't know which way they designed trigger circuit, but if it is "purely digital" (as it is for analog channels) maybe they can implement "AC coupling" on EXT input as well.
And it will be nice if they'll add multiplier setting for the EXT input (0.0001x...1000x) as it is in the channel menu (for correct trigger voltage display).
DS4000 does AC coupling for EXT input as well as voltage multiplier auto sensing.

I'm fairly sure it's not implemented as the same way as the analog channels, at least on the DS2202, because the EXT input is not available for triggering modes other than "Edge". This indicates to me that there isn't a dedicated ADC on the EXT input. (Well, there is a 1-bit ADC, also known as a comparator :P ). The DS4000 is expensive so maybe they sprung for a real ADC, or maybe even real AC coupling (you know, with a capacitor!!!). What trigger modes (e.g. Pulse, Slope, RS232!?) are supported by EXT on the DS4000?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 20, 2014, 01:55:56 pm
Short and not explanatory, but:

Quote
1: We have reproduced the two issues in R&D side;
2: All issues can be fixed by firmware updating without deleting any feature;
3: The trail firmware form R&D will be released in early next week, that can be used for Dave or some urgent cases.

It would be greatly appreciated if they or you would post both the trial firmware and the previous full release version as open downloads instead of having to play the email game to get them.

When they announce availability of a fix, I think everyone who wants a copy should barrage their technical support system and open a case to request it.

Make them fix this ridiculous software distribution method.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 20, 2014, 03:07:28 pm
A cold beer says they will fix the 1000/2000 and ignore the 4000s.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 20, 2014, 04:34:22 pm
The menu options to select AC coupling need to go away on the DS2000A when using the external trigger.  I've confirmed as well that it only supports DC coupling.  You can of course put a cap inline and now you have your AC coupling  :-\

The thing I find amusing about this is that the oscilloscope I use most often has no AC trigger coupling selection for the internal trigger (it supports peak-to-peak triggering instead) but does have selectable AC coupling on the external trigger input.  The reason for this is that the internal trigger can make use of the AC coupling from the vertical input which has been suggested as a work-around for the Rigol oscilloscopes while the external trigger cannot and has to support AC coupling on its own which the Rigol DS2000A series apparently does not.  The Rigol DS1000Z series does not have a problem with this because it relies on its extra vertical inputs as external trigger inputs and they support AC coupling just fine.

There is a parallel here with some of the old portable 4 channel Tektronix oscilloscopes; their two extra channels are limited in only supporting DC coupling like the DS2000A.  Just like with the DS2000A external trigger input, their 3rd and 4th channel cannot remove large DC offsets to pass just the AC signal.  I like to think of them as oscilloscopes with an improved "trigger view" function and 2 external trigger inputs instead of as 4 channel oscilloscopes.  Their extra inputs are very handy for digital logic signals which is probably what Tektronix had in mind.

I don't know which way they designed trigger circuit, but if it is "purely digital" (as it is for analog channels) maybe they can implement "AC coupling" on EXT input as well.
And it will be nice if they'll add multiplier setting for the EXT input (0.0001x...1000x) as it is in the channel menu (for correct trigger voltage display).
DS4000 does AC coupling for EXT input as well as voltage multiplier auto sensing.

I'm fairly sure it's not implemented as the same way as the analog channels, at least on the DS2202, because the EXT input is not available for triggering modes other than "Edge". This indicates to me that there isn't a dedicated ADC on the EXT input. (Well, there is a 1-bit ADC, also known as a comparator :P ). The DS4000 is expensive so maybe they sprung for a real ADC, or maybe even real AC coupling (you know, with a capacitor!!!). What trigger modes (e.g. Pulse, Slope, RS232!?) are supported by EXT on the DS4000?

This is what I concluded about the DS2000A external trigger input as well.  If it was just another digitized input, then it would support all of the trigger modes that the vertical inputs support.  That the external trigger input only supports edge triggering points toward a more traditional analog trigger circuit using a comparator and in the case of the DS2000A, they apparently left out the AC coupling which a vertical input would include.

On the other hand if it was just another digitized input, then why go to the expense of including another digitizer and not have 3 or 4 channels like the DS1000Z series?  This also points toward the external trigger input using an analog trigger design.

What this does not explain however is how Rigol gets the same timing resolution on the DS2000A external trigger input as on the vertical inputs.  Either they had to implement a digital time delay counter in the FPGA logic which is certainly possible or they did something more clever.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alank2 on November 20, 2014, 05:01:55 pm
A cold beer says they will fix the 1000/2000 and ignore the 4000s.

Is the 5uS a ds4k issue?  Or do you mean the ac trigger issue?  Or both?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 20, 2014, 05:04:58 pm
A cold beer says they will fix the 1000/2000 and ignore the 4000s.

Is the 5uS a ds4k issue?  Or do you mean the ac trigger issue?  Or both?

Only item I can reproduce is the delay jitter, but it doesn't alternate from bad to good every 5us, the greater the delay the more bad.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 20, 2014, 06:22:19 pm
Every other manufacturer (and even half of the cheap DIY china scopes) is capable of implementing AC coupled trigger/channel, so where is the problem for Rigol?
there must be something wrong with you:

1- in lot of countries one have to give lot of blowjobs to earn $400 (and cheap does not means bad or broken)
2- fully loaded DS2000A costs nearly $4000, and it does have same shit bug (that should be enought to care, right?)

Man, if I had a dollar for each time the Hantekway DSO crashed on me - or a feature didn't work as advertised - I would have had that $400 lickety-split. I have to say, considering the absolute mess of the FW in the Hantekway, I had to laugh when I read your post, Thomas  ;D

The fact of the matter is that EVERY low-cost Chinese DSO has problems - every single one. The new Siglent SDS2000 was released with 2 of the 4 main acquisition modes not functioning correctly (Peak Detect / High Res) - and that DSO can cost even more than your "fully loaded" figure from above. As a buyer, all you can do is hope that the company will eventually sort out all of the problems (and there are almost always a fair amount of them when new Chinese models are released), and often they will - over time.

And it's fine if you (and others here) claim to use AC-coupled triggering every day. I (and many many others) don't - so as far as bugs go, it's less important to me than, for example, the DSO crashing every hour or so - or the main acquisition modes not functioning correctly.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alank2 on November 20, 2014, 06:22:57 pm
Only item I can reproduce is the delay jitter, but it doesn't alternate from bad to good every 5us, the greater the delay the more bad.

I think it might be something different than the 5us delay jitter issue.  It happens on mine if I push the trigger off the display a bit, with an occasional off screen trigger not always doing it.  I think it has to do with the intensity grading, but perhaps not.  It does not get better and worse though as far as I can tell, but perhaps I need to evaluate it wave by wave to see if the interval is different than 5us...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 20, 2014, 06:45:26 pm
Only item I can reproduce is the delay jitter, but it doesn't alternate from bad to good every 5us, the greater the delay the more bad.

I think it might be something different than the 5us delay jitter issue.  It happens on mine if I push the trigger off the display a bit, with an occasional off screen trigger not always doing it.  I think it has to do with the intensity grading, but perhaps not.  It does not get better and worse though as far as I can tell, but perhaps I need to evaluate it wave by wave to see if the interval is different than 5us...

The jitter is the sum of the jitter from the trigger and the long period jitter from the sampling clock.  It should get worse with longer delays but how much delay are we talking about here?  100s of microseconds?  Milliseconds?

My 2440 can only delay out to 500 microseconds at its highest sampling rate and at that point the added jitter is insignificant although barely measurable and no more than what would be expected from a crystal controlled timebase.  It has less than 200ps of trigger jitter and less than 400ps of total jitter at a delay of 500 microseconds.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: H.O on November 20, 2014, 07:14:57 pm
Quote
Only item I can reproduce is the delay jitter, but it doesn't alternate from bad to good every 5us, the greater the delay the more bad
Quote
The jitter is the sum of the jitter from the trigger and the long period jitter from the sampling clock.
As far as I can see neither the 5us delay issue nor the AC coupled trigger issue have been confirmed on the DS4k. I've tried three times during the week and I can't reproduce it. Yes dr.diesels video does show jitter as the delay gets larger but I'd certainly expect that, especially with a DDS generator (which I don't know if dr.diesel used or not but I am)

Anyway, here's another screenshot from my DS4 with a 10MHz square wave (from DG4162), 25us delay and AC coupled trigger.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 20, 2014, 07:16:05 pm
This is very, very interesting. For context, having the effective holdoff "change" as the timebase is manipulated is standard fare for analog oscilloscopes (or at least, the one analog I've played with).
No, it's really not that interesting if you understand how the DSO works - and it has nothing to do with holdoff per se (although changing the holdoff can affect it). The DS2000 does EITHER Edge triggering - as opposed to ALTERNATING Edge triggering (as many low cost DSOs use) - so having it lock onto a single edge is just simply hitting a multiple of the input frequency and blind time (i.e. waveform update rate) at any particular timebase. You can actually use this "feature" to measure waveform update rate in the absence of a Trigger Out, as I showed in a video I posted here. (https://www.eevblog.com/forum/testgear/a-simple-technique-to-measure-waveform-update-rates-on-dsos-with-no-trigger-out/)

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=119688)

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=119686)

To clarify: there is absolutely NO BUG involving the DS2000's Either Edge triggering - it works just fine.

...at least on the DS2202, because the EXT input is not available for triggering modes other than "Edge".
This is also wrong. It's available as a source to the "Pulse" trigger as well.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jlmoon on November 20, 2014, 07:40:48 pm
A cold beer says they will fix the 1000/2000 and ignore the 4000s.

Is the 5uS a ds4k issue?  Or do you mean the ac trigger issue?  Or both?

Only item I can reproduce is the delay jitter, but it doesn't alternate from bad to good every 5us, the greater the delay the more bad.

5us or 5ns?  I concur with this as well, I see the jitter at 0 - end of graticule on my 2000, not just every other 5ns interval as some are experiencing.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 20, 2014, 07:46:17 pm
Yes dr.diesels video does show jitter as the delay gets larger but I'd certainly expect that, especially with a DDS generator (which I don't know if dr.diesel used or not but I am)

My first video was done with a DG4000, and it was definitely worse than the others, the next two were done with a 16/20Mhz OCXO.

I no longer have anything better than the MSO4000 to test against, and to be completely honest, I rarely run/scroll that far back, on any of my scopes, perhaps I am just expecting too much.

Appreciate those that attempted to recreate.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alank2 on November 20, 2014, 09:01:53 pm
H.O. can you post that same image at T=0?  Does it look better at T=0?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 20, 2014, 09:10:09 pm
I (and many many others) don't - so as far as bugs go, it's WAY less important to me than, for example, the DSO crashing every hour or so - or the main acquisition modes not functioning correctly.

and how much do you use scrolling thru the waveform?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 20, 2014, 09:20:30 pm
I (and many many others) don't - so as far as bugs go, it's WAY less important to me than, for example, the DSO crashing every hour or so - or the main acquisition modes not functioning correctly.

and how much do you use scrolling thru the waveform?

Do you mean while using Delayed Sweep or with Segments? I'm not sure I understand the question (in the context of the bugs we're discussing here), but I would say I use scrolling during about 50% of the DSO usage. Either I'm rarely using it (usually when I'm focused on using the fastest timebases) - or I'm using it a lot (long, slow captures, segments, or bus decoding).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 20, 2014, 09:26:16 pm
BTW, as far as these bugs go - while they are certainly annoying and need to be fixed by Rigol - if I was a new owner of a DS1000Z series, I'd be more pissed about the fact that High Resolution mode doesn't work correctly (certainly not to 12 bits) than I would about these bugs.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: eV1Te on November 20, 2014, 10:33:27 pm
BTW, as far as these bugs go - while they are certainly annoying and need to be fixed by Rigol - if I was a new owner of a DS1000Z series, I'd be more pissed about the fact that High Resolution mode doesn't work correctly (certainly not to 12 bits) than I would about these bugs.

I think the Hi-res mode on the D1000z series averages many measurements for each point (as it is supposed to do), but the resulting values are only 8 bits. So you get less noise due to the averaging, but you never get any higher resolution. (At least not on my DS1074z)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 20, 2014, 10:40:32 pm
No, it's really not that interesting if you understand how the DSO works...

Completely missed the point of my message. I've been saying the whole time, and in my video, that the behaviour of the DS2202 is not a bug, and in fact, superior to a standard analog CRO. Because an analog CRO waits for the sweep to complete before even starting the holdoff, whereas the holdoff on the DS2202 is correct (modulo some fixed error). This is demonstrated in my video.

OK, so that sets the scene: The DS2202 has either edge trigger, and it works beautifully. We're in agreement so far. The other thing I showed is that the triggering behaviour of the DS2202 is not affected in any way by the selected timebase. This is wonderful behaviour. Unless the demonstration I showed in the video was a magical frequency that just happened to behave consistently.

Then, wlanfox comes along and demonstrates that the MSO2202A behaves somewhat differently to the DS2202 -- the trigger behaviour is affected by the selected timebase, and adding one period's worth of holdoff (which should have no effect) has a huge effect. I claim this is very very strange and very very interesting, and I'd like to understand how this is happening (timebase affecting the triggering behaviour kind of makes sense, but the one period's holdoff having no effect makes no sense in any universe.)

To clarify: there is absolutely NO BUG involving the DS2000's Either Edge triggering - it works just fine.

Ya, never claimed otherwise.

...at least on the DS2202, because the EXT input is not available for triggering modes other than "Edge".
This is also wrong. It's available as a source to the "Pulse" trigger as well.

I just tried, and on my firmware, if you select "Pulse" trigger, the channel select turns into a toggle button (as opposed to a scrollable list), pressing it just flicks between CH1 and CH2?  :-//
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 20, 2014, 10:50:52 pm


scrolling i ment in a way the bug was originally reported ie
https://www.youtube.com/watch?v=dHQ4MsMFJTk#t=172 (https://www.youtube.com/watch?v=dHQ4MsMFJTk#t=172)
do you use it like that?
ie i'm asking do you capture it and inspect, or keep it "live" and scroll like in the video above...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 20, 2014, 11:06:04 pm
if I was a new owner of a DS1000Z series, I'd be more pissed about the fact that High Resolution mode doesn't work correctly (certainly not to 12 bits) than I would about these bugs.

What's that issue?
Sorry, I can't up to date with all the posts.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 12:08:20 am
I think the Hi-res mode on the D1000z series averages many measurements for each point (as it is supposed to do), but the resulting values are only 8 bits. So you get less noise due to the averaging, but you never get any higher resolution. (At least not on my DS1074z)

This is normal behavior in High Resolution mode since the DSO has to downsample for the 8-bit display memory as the final step anyway (although it would be handy if it saved the 12-bit values for offloading). But the problem I'm talking about is averaging to 12 bits to begin with - which the DS1000Z is not doing, as far as I've been able to discover so far.

Completely missed the point of my message.

Well, no, I didn't - but I'm guessing you didn't watch my video and so missed the point of my message.

Quote
The other thing I showed is that the triggering behaviour of the DS2202 is not affected in any way by the selected timebase.

Wrong. Watch my video - I change timebases and affect the triggering behavior clear as day on my DS2202.

Quote
Then, wlanfox comes along and demonstrates that the MSO2202A behaves somewhat differently to the DS2202 -- the trigger behaviour is affected by the selected timebase, and adding one period's worth of holdoff (which should have no effect) has a huge effect. I claim this is very very strange and very very interesting, and I'd like to understand how this is happening (timebase affecting the triggering behaviour kind of makes sense, but the one period's holdoff having no effect makes no sense in any universe.)

Again, watch the video; this is easily explained. EACH timebase has an acquisition cycle time - which includes the acquisition time plus the blind time - which is a frequency equivalent to the fastest possible waveforms per second. Frequency multiples falling just outside (or inside, depending on your point of view) of this cycle time will change the triggering behavior.

Quote
I just tried, and on my firmware, if you select "Pulse" trigger, the channel select turns into a toggle button (as opposed to a scrollable list), pressing it just flicks between CH1 and CH2?  :-//

You must be running old firmware.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 12:17:40 am
if I was a new owner of a DS1000Z series, I'd be more pissed about the fact that High Resolution mode doesn't work correctly (certainly not to 12 bits) than I would about these bugs.

What's that issue?
Sorry, I can't up to date with all the posts.

I've yet to discover a timebase/memory setting where the DS1000Z is actually doing 12-bit (256 samples) averaging. I'm not saying for certain that it doesn't happen, but it certainly isn't doing it at anywhere close to the same timebases as the DS2000 - and if it IS actually doing it, it's at very slow timebases.

This "vagueness" in the DS1000Z High Resolution mode is compounded by the way that Rigol defines it in the DS1000Z literature compared to the DS2000:

DS2000 User Manual/Datasheet:
High Resolution
12 bits of resolution when >= 5us/div @ 1 GSa/s (or >= 10us/div @ 500 MSa/s).

DS1000Z User Manual/Datasheet:
High Resolution:
The highest resolution is 12 bit

It would be nice to hear from Rigol the specs of this acquisition mode on the DS1000Z - and when it's actually averaging to 12 bits.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 21, 2014, 12:26:05 am
I've yet to discover a timebase/memory setting where the DS1000Z is actually doing 12-bit (256 samples) averaging. I'm not saying for certain that it doesn't happen, but it certainly isn't doing it at anywhere close to the same timebases as the DS2000 - and if it IS actually doing it, it's at very slow timebases.
DS1000Z User Manual/Datasheet:
High Resolution:
The highest resolution is 12 bit
It would be nice to hear from Rigol the specs of this acquisition mode on the DS1000Z - and when it's actually averaging to 12 bits.

OK, but is this of any importance on a $399 entry level scope?
As long as it does some high resolution boxcar averaging, job done IMO.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 21, 2014, 12:28:48 am
Wrong. Watch my video - I change timebases and affect the triggering behavior clear as day on my DS2202.

Could you please link in this video? I've looked through the past month of your posts and nothing jumped out at me. I vaguely suspect we're talking about different things (waveform updates per second has virtually nothing* to do with what wlanfox and I are discussing [how dual-slope triggering looks], but that's pure idle speculation on my part until I can actually watch your video). A proper  understanding of the behaviour of the DS2202 triggering system must explain what's seen in both of our videos; I look forward to figuring this out.

EDIT: * Oh, unless the very short timebases I was playing with all have exactly the same "acquisition time" as you put it. That's another model that explains what I saw in my video. OK, that's easily tested by varying signal frequency. I feel I probably stand corrected after all.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 12:32:43 am
OK, but is this of any importance on a $399 entry level scope?
As long as it does some high resolution boxcar averaging, job done IMO.

I would think the importance you attach to failures and bugs in features is proportional to the importance those features are to the work you're doing.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on November 21, 2014, 12:39:09 am
OK, but is this of any importance on a $399 entry level scope?
As long as it does some high resolution boxcar averaging, job done IMO.

I would think the importance you attach to failures and bugs in features is proportional to the importance those features are to the work you're doing.
Agreed.
ANY function of a DSO that does not work as expected needs fixing and continued pressure on the manufacturer until it has.
If we collectively continue to accept these shortcomings God help us in the long term.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 12:42:54 am
Could you please link in this video?

There's a link to the video in the first message to you I posted. And I think the graphic I posted shows fairly clearly how a frequency (or multiple of it) that has it's opposite edge falling within the blind time will cause the DSO to lock to the same edge over and over again (very bottom image labelled Either Edge Trigger). This, of course, changes with the timebase - since the blind time changes with the timebase.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on November 21, 2014, 12:57:54 am
I would think the importance you attach to failures and bugs in features is proportional to the importance those features are to the work you're doing.

Sure, but if you buy a $399 scope and expect that to get the utmost in performance from the hires mod when all they can spec is "The highest resolution is 12 bit" (which I read as "upto 12 bits, maybe, at one single sweet spot when the moon is full, kinda sorta"), then you are probably expecting too much?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 01:22:35 am
Sure, but if you buy a $399 scope and expect that to get the utmost in performance from the hires mod when all they can spec is "The highest resolution is 12 bit" (which I read as "upto 12 bits, maybe, at one single sweet spot when the moon is full, kinda sorta"), then you are probably expecting too much?

Absolutely; no doubt about that - although their reluctance to actually specify the parameters makes me wonder if it really does manage to do 12-bits at all - even when the moon is full  :)  - or whether that's their attempt to make it seem as if the feature is closer in performance to the other UltraVision models than it really is. I've tested timebases down to about 50 or 100ms and haven't seen any 12-bit averaging. But as you say, it does some averaging, so it's fine for most people - unless they really expected to be getting 12-bit equivalent resolution regularly (and really need that much filtering for their work).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 21, 2014, 07:34:50 am
OK, but is this of any importance on a $399 entry level scope?
As long as it does some high resolution boxcar averaging, job done IMO.
The point is that the high resolution mode doesn't seem to work as you would expect. The DS1K doesn't seem to be adding the 1LSB of Gaussian noise needed in order to achieve higher than 8bit resolution. All it seems to achieve is a slightly less noisy 8bit signal, negating any benefit of having >256px vertical display resolution. If you add 1LSB of noise externally, it does achieve >8bit. edit: maybe not.

Compare it to this MDO3000 which has a beautifully working hires mode (jump to 4:50):
https://www.youtube.com/watch?v=c6I7Ycbv8B8 (https://www.youtube.com/watch?v=c6I7Ycbv8B8)

I'm well aware of the price difference between an MDO3000 and a DS1000Z, but Rigol are being cheeky to claim that box car averaging alone is 'high resolution mode'.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: thn788 on November 21, 2014, 12:58:44 pm
For those of us, who are not "well aware of the price difference between an MDO3000 and a DS1000Z": the Rigol DS1054Z costs $399, the Tek MDO3104, which is shown in the linked video, costs $13,900.  ;)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 01:31:04 pm
The point is that the high resolution mode doesn't seem to work as you would expect. The DS1K doesn't seem to be adding the 1LSB of Gaussian noise needed in order to achieve higher than 8bit resolution. All it seems to achieve is a slightly less noisy 8bit signal, negating any benefit of having >256px vertical display resolution....
...but Rigol are being cheeky to claim that box car averaging alone is 'high resolution mode'.
I think you're confused between how you expect High Res mode should work, how it's actually supposed to work, and how well the DS1000Z achieves it's results.

Rigol is neither the source of claims about averaging - nor the company that first named it High Res (I believe that honor goes to Tektronix - see image below from 2003 Tek paper on acquisition modes).

There are papers detailing the effects of successive sample averaging (also called boxcar filtering or moving average filtering), such as:
http://www.daysalive.com/share/EffectsofAveragingtoRejectUnwanted Signals.pdf (http://www.daysalive.com/share/EffectsofAveragingtoRejectUnwanted Signals.pdf)
...but the main points are that it removes noise by decreasing a DSO’s bandwidth (it applies an LPF function with a -3dB point approximated by 0.433*sample rate/averaged samples), achieving 1 bit of effective resolution improvement for each factor of four of averaged samples (e.g. 4 bits improvement = 256 averaged samples).

The DS2000 does a good job of implementing 256 sample averaging in real-time (functioning almost identically to the Agilent X-Series), but the DS1000Z does not - I'm guessing because the engine is not fast enough to support it (except perhaps at very slow timebases). The difference between the two DSOs is quite apparent, so the problem isn't with the technique but the implementation on the DS1000Z.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 21, 2014, 02:13:05 pm
I received a response from Rigol this am in reference to the ticket I created early this week with them about these issues.  It seems they may be in denial that most all DS1000Z series have this issue or maybe they just want verification.  I received this scope last Friday.
Here is the message I received.  I left the names out.

"We are aware of a potential issue with the DS1000Z series.

Have you experienced the issue or is it in response to information that you found?

I have attached our preliminary research based on Dave Jones' EEVBlog tests.
Can you take a look at the document, perform the self calibration after warm-up, and let me know if the issue persists?

We will surely cover the return, even if it is past 30 days."
 
Here is the pdf document and a screenshot of my DS1054Z.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 21, 2014, 02:30:37 pm
Rigol is neither the source of claims about averaging - nor the company that first named it High Res (I believe that honor goes to Tektronix - see image below from 2003 Tek paper on acquisition modes).

Tektronix referred to high resolution mode at least as far back as 1992 when it was included in the TDS400 series of DSOs.  Distinct from this, they used the terms "smoothing" for DSP filtering and "averaging" for multiple acquisitions years earlier.

The scan I included is from their 1993 catalog.  Their November 1991-1992 Product Catalog Supplement released in 1992 mentions high resolution mode and these oscilloscopes as well.

At least in the TDS400 series, their high resolution mode only produced results up to 15 bits because of word size limitations.  I assume from the earlier discussion that the DS2000A series works similarly and the DS1000Z series is limited to 8 bit results making its high resolution mode more of a noise reduction mode.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 21, 2014, 02:45:23 pm
I received a response from Rigol this am in reference to the ticket

We've seen that shit before, they sent you the same thing that has been in circulation here for a while.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 21, 2014, 03:16:45 pm
2nd email from them this AM in response to the questions document.

"Ok. Excellent. Thank you very much for the video.

We haven't been able to reproduce the issue on units that we have here.

Would you be willing to be without the scope for a week or so?

We would like to ask if you could ship the scope to us (we will send you a FedEx label.. just need you to box it up and ship it) for further testing?

We will test it with beta firmware revisions and then ship it back once we have a solid fix in place.

WRT the 30 day return.. we are extending it until we get the fix from Engineering.. so, no risk from that standpoint"


Are you kidding me!  I have a hard time believing they have no scope to test with.  They want to use my personal scope for testing???  Seems like a mickey mouse operation.  Lets see... I purchase a new scope so they can do R&D.
I am very disappointed in the way this whole thing has been handled.  This is the last Rigol product I will purchase.

Rigol, Send me one of the working scopes you have. and I will gladly send you this broken one for R&D.  :wtf:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 03:45:18 pm
Tektronix referred to high resolution mode at least as far back as 1992 when it was included in the TDS400 series of DSOs.  Distinct from this, they used the terms "smoothing" for DSP filtering and "averaging" for multiple acquisitions years earlier.

The scan I included is from their 1993 catalog.  Their November 1991-1992 Product Catalog Supplement released in 1992 mentions high resolution mode and these oscilloscopes as well.

Thanks for the added info; I assumed it was earlier than 2003, but had no idea when the feature was first developed.

Quote
At least in the TDS400 series, their high resolution mode only produced results up to 15 bits because of word size limitations.  I assume from the earlier discussion that the DS2000A series works similarly and the DS1000Z series is limited to 8 bit results making its high resolution mode more of a noise reduction mode.

There seems to be a bit of confusion about how DSOs display the final result of the averaging. You'll notice in your Tek scan that it says:

"Vertical Resolution - 8 bits (256 levels over 10.24 vertical divisions)"

and then later:

"Hi-Res - Vertical resolution improvement and noise reduction on low frequency signals..."

It doesn't say:

"Vertical Resolution - 8 bits (except when in Hi-Res mode...etc.)"

The resolution or scale of the display doesn't change automatically somehow in Hi-Res mode. As far as I'm aware, all DSOs that do Hi-Res downsample the final results to the 8-bit display (or display memory). They have to - they don't even have the display resolution to manage 9-bits, let alone 12 - otherwise the scale would suddenly shift dramatically. But the DS2000A is definitely averaging 256 samples (4 effective bits) before downsampling for the display, while the DS1000Z appears to be doing mainly just 2 or maybe 3 bits (16 or 64 samples).

I'm not sure about Tek's implementation, but where Rigol's implementation on the DS2000A differs from, for example, Agilent's X-series (unfortunately), is that Rigol doesn't save the results of the averaging in sample memory for downloading to an external device as 12-bit values.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 21, 2014, 04:06:56 pm
The point is that the high resolution mode doesn't seem to work as you would expect. The DS1K doesn't seem to be adding the 1LSB of Gaussian noise needed in order to achieve higher than 8bit resolution. All it seems to achieve is a slightly less noisy 8bit signal, negating any benefit of having >256px vertical display resolution....
...but Rigol are being cheeky to claim that box car averaging alone is 'high resolution mode'.
I think you're confused between how you expect High Res mode should work, how it's actually supposed to work, and how well the DS1000Z achieves it's results.

Rigol is neither the source of claims about averaging - nor the company that first named it High Res (I believe that honor goes to Tektronix - see image below from 2003 Tek paper on acquisition modes).

There are papers detailing the effects of successive sample averaging (also called boxcar filtering or moving average filtering), such as:
http://www.daysalive.com/share/EffectsofAveragingtoRejectUnwanted Signals.pdf (http://www.daysalive.com/share/EffectsofAveragingtoRejectUnwanted Signals.pdf)
...but the main points are that it removes noise by decreasing a DSO’s bandwidth (it applies an LPF function with a -3dB point approximated by 0.433*sample rate/averaged samples), achieving 1 bit of effective resolution improvement for each factor of four of averaged samples (e.g. 4 bits improvement = 256 averaged samples).

The DS2000 does a good job of implementing 256 sample averaging in real-time (functioning almost identically to the Agilent X-Series), but the DS1000Z does not - I'm guessing because the engine is not fast enough to support it (except perhaps at very slow timebases). The difference between the two DSOs is quite apparent, so the problem isn't with the technique but the implementation on the DS1000Z.
I know how 'high-res'/oversampling works. The issue is that the DS1000Z is doing something wrong because there is an apparent lack of increased resolution when the high res mode is turned on.

You can only achieve increased resolution if there exists 1LSB (or more) of Gaussian noise on the signal. If the signal is not sufficiently 'noisy' within the window of the averaging filter, it won't work properly. For example, you feed in a DC signal that falls somewhere between quantization levels '232' and '233' of the 8-bit ADC, but the ADC outputs '233' consecutively since the signal is closer to 233 than 232. You apply box car averaging to a long string of 233s and you still get 233, the result is no increased resolution.
Now if you add 1LSB of analog noise before the ADC, the ADC will output out a series of samples which alternate between 232 and 233, with a distribution that when averaged will give a value that is in between 232 and 233, thus increasing the resolution beyond the number of quantization levels of the DAC.

If the DS1000Z isn't adding 1LSB of noise internally, then it is obviously not going to guarantee increased resolution in every circumstance. I haven't been successful in getting significantly increased resolution out of my DS1000Z, even when attempting to add external noise there are still obvious 8bit quantization levels present (it jumps up/down by 2 pixels in places instead of 1). I'm not 100% sure why this is. I suspect the result might be rounded back to 8bit somewhere before it is rendered on the screen. The high res mode is obviously doing some averaging, it just doesn't seem to increase the resolution. The intensity grading also effectively does some averaging (but not in a way that would increase resolution), which makes it even harder to observe what is going on.

On some vertical ranges there is even less than 8bits of resolution displayed on the screen. Every time you hear a relay click, you are changing the real analog range being fed into the ADC, so certain ranges have 8bit and some are effectively 7 or maybe even 6 bit. It wouldn't be such an issue if the high res mode worked properly!

Tektronix scopes implement high-res correctly and consistently achieve increased resolution that pretty much matches the display resolution, even for noiseless DC. I'm not sure how/if the DS2000 does it because I don't recall seeing anyone demonstrate it and haven't had the chance to get my hands on one.

You do not need 256 sample averaging to increase the resolution. Even if the 1000Z can only do 16sample wide windows, it should still achieve 12-bit resolution. 256 sample window would achieve 16bit. It really only needs 9bit since the display isn't even 512pixels tall...

That said, complaining that a $400 scope can't do high res properly would be a bit rich, i just think that 'high-res' is an inaccurate description of what it is doing. 'Noise reduction' or 'HF reject' would be a better description.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 21, 2014, 04:13:41 pm
The resolution or scale of the display doesn't change automatically somehow in Hi-Res mode. As far as I'm aware, all DSOs that do Hi-Res downsample the final results to the 8-bit display (or display memory). They have to - they don't even have the display resolution to manage 9-bits, let alone 12. But the DS2000A is definitely averaging 256 samples (4 effective bits) before downsampling for the display, while the DS1000Z appears to be doing just 2 or 3 bits (16 or 64 samples).

Did I say that?

The scale of the display does not change but the waveform record is not 8 bits in the case of the TDS series and similar old Tektronix DSOs and does not even match their digitizer resolution.  I have assumed that the Rigol oscilloscopes do something similar to the old Tektornix DSOs but are they more limited?

Quote
I'm not sure about Tek's implementation, but where Rigol's implementation on the DS2000A differs from, for example, Agilent's X-series (unfortunately), is that Rigol doesn't save the results of the averaging in sample memory for downloading to an external device as 12-bit values.

On the DSOs I am familiar with which operate in a way similar to the TDS420, the waveform record is greater than 8 bits and usually 16 bits.  High resolution mode returns an acquisition record with more than 8 bits of resolution and averaging during post processing also produces a waveform record with more than 8 bits.  I can visually verify this on the Tektronix DSOs I have, including the old ones, by saving and vertically magnifying the display record which will not show 8 bit quantization.  The TDS series and some earlier ones will do this in averaging mode in real time to produce more sensitive vertical scales.  I do not remember if the TDS series will do the same in high resolution mode as I have not used one in 20 years but I think they do.  Automatic measurements work on the higher resolution waveform record as well.

Without high resolution mode, averaging, or smoothing, it is just 8 bit data of course.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 21, 2014, 04:17:15 pm
You can only achieve increased resolution if there exists 1LSB (or more) of Gaussian noise on the signal. If the signal is not sufficiently 'noisy' within the window of the averaging filter, it won't work properly.

It would be an unusual DSO vertical signal chain which does not inherently have sufficient noise to meet this requirement.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 04:31:23 pm
I know how 'high-res'/oversampling works. The issue is that the DS1000Z is doing something wrong because there is an apparent lack of increased resolution when the high res mode is turned on.

It doesn't sound like you do.

You can only achieve increased resolution if there exists 1LSB (or more) of Gaussian noise on the signal. If the signal is not sufficiently 'noisy' within the window of the averaging filter, it won't work properly.

According to who? I posted a paper that clearly documents both the mathematical method and effect of successive sample averaging - which, BTW, doesn't mention anywhere "adding 1LSB of noise" - but you've not posted any substantiating material.

Quote
I haven't been successful in getting any increased resolution out of my DS1000Z, even when attempting to add external noise there are still obvious 8bit quantization levels present (it jumps up/down by 2 pixels in places instead of 1). I'm not 100% sure why this is. I suspect the result might be rounded back to 8bit somewhere. The high res mode is obviously doing some averaging, it just doesn't seem to increase the resolution.

I'm not sure what you mean by "increasing the resolution" - it seems you didn't read the paper on how it works. The DS1000Z is definitely increasing the effective resolution - but by only 2 or 3 bits - I can see this clearly on the DS1000Z I have.

Quote
Tektronix scopes implement high-res correctly and consistently achieve increased resolution, even for noiseless DC.

Again, I'm afraid you would need to post actual documentation proving your assertions.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 21, 2014, 04:33:36 pm
UPDATE FROM RIGOL

Short and not explanatory, but:

Quote
1: We have reproduced the two issues in R&D side;
2: All issues can be fixed by firmware updating without deleting any feature;
3: The trail firmware form R&D will be released in early next week, that can be used for Dave or some urgent cases.

This update must be false as I received an email from them this AM stating:

 "Ok. Excellent. Thank you very much for the video.

We haven't been able to reproduce the issue on units that we have here.

Would you be willing to be without the scope for a week or so?

We would like to ask if you could ship the scope to us (we will send you a FedEx label.. just need you to box it up and ship it) for further testing?

We will test it with beta firmware revisions and then ship it back once we have a solid fix in place.

WRT the 30 day return.. we are extending it until we get the fix from Engineering.. so, no risk from that standpoint."
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Monkeh on November 21, 2014, 04:38:17 pm
UPDATE FROM RIGOL

Short and not explanatory, but:

Quote
1: We have reproduced the two issues in R&D side;
2: All issues can be fixed by firmware updating without deleting any feature;
3: The trail firmware form R&D will be released in early next week, that can be used for Dave or some urgent cases.

This update must be false as I received an email from them this AM stating:

 "Ok. Excellent. Thank you very much for the video.

We haven't been able to reproduce the issue on units that we have here.

Would you be willing to be without the scope for a week or so?

We would like to ask if you could ship the scope to us (we will send you a FedEx label.. just need you to box it up and ship it) for further testing?

We will test it with beta firmware revisions and then ship it back once we have a solid fix in place.

WRT the 30 day return.. we are extending it until we get the fix from Engineering.. so, no risk from that standpoint."

Alternatively, the person who emailed you was not informed..
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 21, 2014, 04:45:42 pm
You can only achieve increased resolution if there exists 1LSB (or more) of Gaussian noise on the signal. If the signal is not sufficiently 'noisy' within the window of the averaging filter, it won't work properly.

According to who? I posted a paper that clearly documents both the mathematical method and effect of successive sample averaging - which, BTW, doesn't mention anywhere "adding 1LSB of noise" - but you've not posted any substantiating material.

From the paper that you posted:
Quote from: 'the paper'
Resolution will
always be improved on those portions of a signal that slew
through multiple code counts between samples, but steady-state
signals will see improvement only if there is noise present with
amplitude greater than 1 or 2 ADC LSBs.
Obviously if the size of the window of the filter is small with respect to the input signal transitioning through LSBs of the ADC, the signal itself will not fit the requirements for increased resolution. Adding 1LSB of noise solves that problem entirely.

You yourself raised concern that the DS1000Z did not have the processing power to use a large enough averaging window...

Quote
Tektronix scopes implement high-res correctly and consistently achieve increased resolution, even for noiseless DC.

Again, I'm afraid you would need to post actual documentation proving your assertions.
Observe the youtube video i linked in Reply #390. It is obvious that there is FAR more than 8 bits of resolution on the display as there is no significant pixelation visible even though the signals are scaled to only a small fraction of the vertical span on the display. Doing the same on the DS1000Z results in bulk pixelation due to lack of sampling resolution.

The DS1000Z is definitely increasing the effective resolution - but by only 2 or 3 bits - I can see this clearly on the DS1000Z I have.
I'm afraid you would need to post actual documentation proving your assertions.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 21, 2014, 04:53:25 pm
Normal mode
(https://farm9.staticflickr.com/8610/15843297661_8c34406cc2_o.png)

'Hi res' mode
(https://farm9.staticflickr.com/8630/15843297681_074d2f488e_b.jpg)

There is no obvious increase in resolution to my eyes, in fact i think 'hi res' looks subjectively worse as the averaging removes noise and makes the quantization levels even more obvious.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 04:54:29 pm
The scale of the display does not change but the waveform record is not 8 bits in the case of the TDS series and similar old Tektronix DSOs and does not even match their digitizer resolution.

Yes - the waveform record (or sample memory) - but this is irrelevant to the real-time display of the waveform, only to external post processing.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 21, 2014, 05:02:55 pm
(https://farm9.staticflickr.com/8630/15843297681_074d2f488e_b.jpg)
With that resolution, how hard would displaying anti-aliased graphics be? I would sacrifice waveform update rate with accuracy.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 05:21:24 pm
From the paper that you posted:
Quote from: 'the paper'
Resolution will always be improved on those portions of a signal that slew through multiple code counts between samples, but steady-state signals will see improvement only if there is noise present with amplitude greater than 1 or 2 ADC LSBs.

I'm afraid:

"...steady-state signals will see improvement only if there is noise present with amplitude greater than 1 or 2 ADC LSBs"

...is quite different from your statement that:

"You can only achieve increased resolution if there exists 1LSB (or more) of Gaussian noise on the signal."

Quote
Adding 1LSB of noise solves that problem entirely.

That would be assuming it's a "problem that needs to be solved", rather than a simple case that doesn't fit within the parameters of resolution improvement affected by successive sample averaging.

Quote
Observe the youtube video i linked in Reply #390. It is obvious that there is FAR more than 8 bits of resolution on the display as there is no significant pixelation visible even though the signals are scaled to only a small fraction of the vertical span on the display.

I observed the video - it proves nothing about Tektronix adding 1LSB of noise. Whatever averaging it's doing has to be eventually downsampled for the 400 pixels of vertical resolution. Could you please post some documentation from Tektronix that describes them introducing 1LSB of noise before successive sample averaging? That alone would convince me that they're doing it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 21, 2014, 05:32:28 pm
Guys sorry for jumping in. This thread is for the Jitter problem . Unless i misunderstood , may i suggest the Hi-Res discussion to be moved to a separate topic.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TMM on November 21, 2014, 05:37:41 pm
If the signal already slews through multiple LSBs between samples, either:
a) There is noise present on the signal of interest with multiple-LSB amplitude :-+
b) The resolution limitation is now the time domain instead of vertical resolution. If each sample point moves multiple pixels, the effect of hi-res mode is pretty pointless. Time domain interpolation is now required for a visual resolution increase.

I observed the video - it proves nothing about Tektronix adding 1LSB of noise. Whatever averaging it's doing has to be eventually downsampled for the 400 pixels of vertical resolution. Could you please post some documentation from Tektronix that describes them introducing 1LSB of noise before successive sample averaging? That alone would convince me that they're doing it.
Tek inject a 'dither' signal for the spectrum analyzer function of the MDO3000/4000. In their own words (http://www.tek.com/dl/48W-28882-2%20%20%20MDO%20Performance%20WP_.pdf (http://www.tek.com/dl/48W-28882-2%20%20%20MDO%20Performance%20WP_.pdf)):
Quote from: 'tek'
Dither is a random signal that is added to the input signal to smear its energy across multiple A/D codes, effectively averaging the individual DNL errors across all the codes.
I see no reason they would not use the same function on the MDO3000 when it is in high-res oscilloscope mode. Of course i cannot confirm nor deny that they actually are doing this but it certainly behaves like it does, and the Rigol certainly behaves like it does not. ADCs will introduce some of their own noise when run at their full sample rate, but the gains in resolution by averaging/down-sampling are not nearly as good as when normally distributed analog noise is injected.

Guys sorry for jumping in. This thread is for the Jitter problem . Unless i misunderstood , may i suggest the Hi-Res discussion to be moved to a separate topic.
good idea.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: eV1Te on November 21, 2014, 06:16:27 pm
Guys sorry for jumping in. This thread is for the Jitter problem . Unless i misunderstood , may i suggest the Hi-Res discussion to be moved to a separate topic.

I do not think it is to far off topic to mention other bugs to the same instrument, but I will just add my measurements of the Hires bug as a final say to this topic, if anyone else wants to argue that it is not a bug at all, then it might be appropriate to start a new topic regarding this issue.
 
Here are some captures in Normal, Hires and Averaging 256. I stopped the scope at 100 mV vertical, and in stopped mode I increased the vertical to 10 mV (10 times), in order to see the quantization of the bits (you still see it without increasing vertical but it is more clear this way).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 21, 2014, 06:20:08 pm
The scale of the display does not change but the waveform record is not 8 bits in the case of the TDS series and similar old Tektronix DSOs and does not even match their digitizer resolution.

Yes - the waveform record (or sample memory) - but this is irrelevant to the real-time display of the waveform, only to external post processing.

The vertical scale on the TDS series has a separate zoom function which operates in real time.  The later pre-TDS series DSOs handle the zoom a little differently but it operates in real time when averaging is used.

Of course no additional resolution is displayed by zoom except when average or higher resolution mode is used to provide it but when that is done, the greater than 8 bit results can be displayed.  On my 2440, saved or real time waveforms will show quantization unless averaging was used during their acquisition and zoom may only be used on real time waveforms when averaging is used.  On a 2230 or 2232, the same applies but zoom only works on saved waveforms.  From what I remember of the TDS series, high resolution mode may be used in place of averaging for this so an acquisition record of greater than 8 bits is created and transferred to the waveform memory.

To sum up the above, the waveform record on these oscilloscopes is greater than 8 bits and may be displayed in real time showing resolutions greater than 8 bits when averaging or high resolution mode is used during acquisition.

I have to defer to you and others about how the Rigol DSOs work in regard to the above.  I did not get around to testing this aspect of their operation when I was evaluating them.  Some of their known quirks like making automatic measurements on the display record imply problems.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 21, 2014, 06:26:46 pm
With that resolution, how hard would displaying anti-aliased graphics be? I would sacrifice waveform update rate with accuracy.

It looks to me like an anti-aliased display of an 8 bit waveform.  I assume Rigol used an 8 bit waveform record and processing to preserve the highest possible update rate.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 21, 2014, 06:54:26 pm
Guys sorry for jumping in. This thread is for the Jitter problem . Unless i misunderstood , may i suggest the Hi-Res discussion to be moved to a separate topic.

I do not think it is to far off topic to mention other bugs to the same instrument,

Yes fair to say so but a new reader may think that Hi-Res mode has to do with the jitter problem, which it does not...
 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 21, 2014, 06:56:02 pm
UPDATE FROM RIGOL

Short and not explanatory, but:

Quote
1: We have reproduced the two issues in R&D side;
2: All issues can be fixed by firmware updating without deleting any feature;
3: The trail firmware form R&D will be released in early next week, that can be used for Dave or some urgent cases.

This update must be false as I received an email from them this AM stating:

 "Ok. Excellent. Thank you very much for the video.

We haven't been able to reproduce the issue on units that we have here.

Would you be willing to be without the scope for a week or so?

We would like to ask if you could ship the scope to us (we will send you a FedEx label.. just need you to box it up and ship it) for further testing?

We will test it with beta firmware revisions and then ship it back once we have a solid fix in place.

WRT the 30 day return.. we are extending it until we get the fix from Engineering.. so, no risk from that standpoint."

Alternatively, the person who emailed you was not informed..

Should that make us feel better?  I think they will be getting a bunch of them in for testing soon.   
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on November 21, 2014, 07:21:07 pm
Are you kidding me!  I have a hard time believing they have no scope to test with.  They want to use my personal scope for testing???  Seems like a mickey mouse operation.  Lets see... I purchase a new scope so they can do R&D.
I am very disappointed in the way this whole thing has been handled.  This is the last Rigol product I will purchase.

Rigol, Send me one of the working scopes you have. and I will gladly send you this broken one for R&D.  :wtf:

Maybe they outsourced design and production (to whom?) to keep costs low and really do not have any of their own DSOs or test equipment to work with.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 21, 2014, 07:41:16 pm
From what I remember of the TDS series, high resolution mode may be used in place of averaging for this so an acquisition record of greater than 8 bits is created and transferred to the waveform memory.

Well, luckily there's this newfangled contraption called The Internet that can supplement memory :)  Unfortunately, after much digging, I can find no documentation that any Tektronix DSO/MSO specifically creates waveform records of greater than 8 bits when using Hi-Res - but perhaps you can dig up some evidence to support this.

Quote
To sum up the above, the waveform record on these oscilloscopes is greater than 8 bits and may be displayed in real time showing resolutions greater than 8 bits when averaging or high resolution mode is used during acquisition.

You are summing up your opinions - which, again, have yet to be supported with any documentation. And while I don't doubt that Tektronix scopes could slice bread if inserted correctly, I'm afraid I would need to see documentation from Tek describing the workings of that feature.

Quote
Some of their known quirks like making automatic measurements on the display record imply problems.

Oh my! You mean exactly like the Agilent X-series and virtually every other low-cost DSO on the market does? Does that mean that ALL of those DSO's have problems?  ;D
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: H.O on November 21, 2014, 07:42:42 pm
H.O. can you post that same image at T=0?  Does it look better at T=0?

Hi,
Sure. Attached is a montage of 4 different screenshots. T=0, T=5us, T=15us and T=105us. Same 10MHz Square wave from DG4162, 50% dutycycle. Input DC coupled, trigger AC coupled. For reference, this is on a DS4k.

As you can see it does a look a bit better at T=0 and gets progressively worse as T increases (as expected). It's not much of a difference between T=0 and T=15 but it's clearly vissible at T=105us.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rf-loop on November 21, 2014, 10:18:32 pm

Well, luckily there's this newfangled contraption called The Internet that can supplement memory :)  Unfortunately, after much digging, I can find no documentation that any Tektronix DSO/MSO specifically creates waveform records of greater than 8 bits when using Hi-Res

Really? Or is this some kind of joke.

Simple case if people have enough real work working experience with digital scopes.  Peoples in this forum have so different knowledge and specially so different experience with test equipments including also last 30 years digital scopes.

Tektronix many TDS models do it sure. Even my  old TDS520 what is partially retired last years.


In Hi-Res mode it use double amount of capture memory - why? Because in thiss mode it store 2 bytes for one (calculated) data point. (it is 16 bit)
It produce this using averaging (high res mode type of averaging)

In normal mode it store of course 8 bit raw ADC data.

Where are documents?

Of course these are documented in this serie scopes manuals.

And extremely clearly.

Take example TDS series programmers manual (TDS410 up to TDS 784)

Look then example page where is explained command  DATa:WIDth   and also related command CURVe. Perhaps it proofs this enough.

No need more this OT.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 22, 2014, 01:30:06 am
Take example TDS series programmers manual (TDS410 up to TDS784).

Thank you! I just wanted to be pointed in the direction of relevant documentation and there are a lot of Tek documents and manuals (and TDS models) - so I clearly wasn't finding the correct ones.

But I found a ton of useful information, including, yes, confirmation of their 16-bit waveform records, a detailed description of their Hi Res technique (which certainly does not involve introducing noise or injecting a dither signal), and a chart specifying their downsampling from Hi Res mode to the display graticule on the TDS XXXA series (which seems to be quite similar to the Rigol DS2000, since they both normally map their ADCs to 10 vertical divisions).

Anyway, thanks again for the tip - will refrain from further discussion of Hi Res.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 22, 2014, 12:28:06 pm
2nd email from them this AM in response to the questions document.

"Ok. Excellent. Thank you very much for the video.

We haven't been able to reproduce the issue on units that we have here.

Would you be willing to be without the scope for a week or so?

We would like to ask if you could ship the scope to us (we will send you a FedEx label.. just need you to box it up and ship it) for further testing?

We will test it with beta firmware revisions and then ship it back once we have a solid fix in place.

WRT the 30 day return.. we are extending it until we get the fix from Engineering.. so, no risk from that standpoint"


Are you kidding me!  I have a hard time believing they have no scope to test with.  They want to use my personal scope for testing???  Seems like a mickey mouse operation.  Lets see... I purchase a new scope so they can do R&D.
I am very disappointed in the way this whole thing has been handled.  This is the last Rigol product I will purchase.

Rigol, Send me one of the working scopes you have. and I will gladly send you this broken one for R&D.  :wtf:

Rigol sent another email stating they are going to send a new working scope to exchange the broken one for use to troubleshoot these issues.   :-+ 
Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 22, 2014, 06:26:59 pm



In Hi-Res mode it use double amount of capture memory - why? Because in thiss mode it store 2 bytes for one (calculated) data point. (it is 16 bit)
It produce this using averaging (high res mode type of averaging)


No need more this OT.

if i now write this in rigol z thread, nobody will read it, but yes, mods should move some of this thread that way:

first, what does averaging have to do with "hires"?
if you ask me, nothing. you still have the same crappy screen resolution.

2nd, graticule of z series is 25pix per div, which yields 300x200 resolutuion (cropped graticule negative down, just zoom and count pixels), and these screens look exactly like that....screenshits. never mind 800x480 screen, it's not even close.

now i'm afraid even to think about 1052 resolution, it's essentially a toy...
(https://lh6.googleusercontent.com/-hW5M7h84BFo/Udb4OXiiTVI/AAAAAAAAUkE/uQqPmiBzmzI/s400/rigol-cursor.jpg)
scarry really...  :palm:
(yes, 1052 scarier, but z is also very low res)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 22, 2014, 06:37:48 pm
first, what does averaging have to do with "hires"?

As already mentioned: Hi Res = successive sample averaging (i.e. boxcar filtering).

Quote
2nd, graticule of z series is 25pix per div, which yields 300x200 resolutuion (cropped graticule negative down, just zoom and count pixels)

Graticule of Z series = 50px per div / Waveform display area = 12x8 divs = 700x400px

EDIT: Added cropped image from Photoshop - no need to count pixels.

EDIT2: BTW, starting a new thread in a couple of minutes to discuss any/all anomalies/bugs in/between UltraVision models.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 22, 2014, 06:54:26 pm
no, count them (you can count them on your image too, it's easier than my image), unlesss there's a display setting i missed, and i doubt it, i searched the display menu last nite esp. because of screens like this (and also because i'm into video on pc, so i recognize lores instantly).

you do see that even though screen res is higher, the only resolution you get in the waveform is the one of graticule, right?
count graticule dots, nothing else. 

i understand what is said about hires mode, ie how it works (ie ...every pixels becomes a merger of surrounding pixels around it) but that has nothing to do with screen resolution in any way...
i would call this false advertising.
hires would mean more pixels, more dots, no matter if you speak about television, or the scope.
more pixels=better.
that's why i sadi this scope whould have hdmi 1080p output.
and a display processor to go with it (not just to output this lores crap via hdmi but to have a true 1080p resolution).
and improved sampling system (better to say vertical resolution of more than freaking 8bits!), if needed...heh

and i think anti-aliasing option in the scope has nothing to do with display, but with acquisition, i'm mentioning this because in video and games the anti-aliasing term means "to remove stair-stepping jaginess".
here i would say it probably limits the input to nyquist or alike (i'm guessing).
(too lazy to check the rigol manual (which lacks the menu tree, btw. the only thing i wanted to see in it, it lacks!) but you'll correct me if i'm wrong....)

edit_x: but just the rigol UI inconsistencies alone need the separate thread!  :-//
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 22, 2014, 07:08:37 pm
damn!
i missed every other pixel!
 :palm:

it's like you say.

guess i should watch screenshots from higher distance on pc monitor.  :-DD

edit/ hold on a bit there: vertical resolution is half the one you stated, 200pixels like i originally said, because you have 2 vertical pixels as smallest possible sample....ie 2 vertical pixels are one colour ie one pixel. they align nicely on the right side of the graticule.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 22, 2014, 07:11:04 pm
no, count them (you can count them on your image too, it's easier than my image), unlesss there's a display setting i missed, and i doubt it, i searched the display menu last nite esp. because of screens like this (and also because i'm into video on pc, so i recognize lores instantly).

Are you just counting the tick marks on the graticule division lines? Because, if so, that's not the resolution - the resolution of the graticule is ALL screen pixels between two major division lines - in other words, 50 pixels on the UltraVision models (as clearly shown by Photoshops rulers). I can easily post an image showing all of the pixels being used.

EDIT: Whoops - I just saw you posted a correction - so nevermind  :)

Quote
i understand what is said about hires mode, ie how it works (ie ...every pixels becomes a merger of surrounding pixels around it) but that has nothing to do with screen resolution in any way...
i would call this false advertising.

I would agree that it's not the best way to describe the feature - I would prefer that DSOs used "Waveform Average" instead of "Average", and "Sample Average" instead of "Hi Res" - but as mentioned earlier, the name appears to have been invented by Tektronix.

Quote
and i think anti-aliasing option in the scope has nothing to do with display, but with acquisition, i'm mentioning this because in video and games the anti-aliasing term means "to remove stair-stepping jaginess".

This is a whole other problem with the Rigol UltraVision DSOs - but I think we should discuss it at the new thread I'm creating  ;)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 22, 2014, 07:18:23 pm
Quote
but as mentioned earlier, the name appears to have been invented by Tektronix.
it would be wrong even if einstein invented it!  :-DD

i would call it what it is "spatial averaging". a name from video tech, where you do exactly the same thing with some filters.

Quote
EDIT: Whoops - I just saw you posted a correction - so nevermind

i posted one more correction, and it's a good one!  ;)

this explains crappy resolution, it's the vertical!
it is causing jaggies!
http://en.wikipedia.org/wiki/Jaggies (http://en.wikipedia.org/wiki/Jaggies)

tru(tm) resolution of these scopes is 700x200!

and you've guessed it, setting it from vector to raster mode does nothing.

i see more and more lies here!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 22, 2014, 07:32:54 pm
tru(tm) resolution of these scopes is 700x200!

and you've guessed it, setting it from vector to raster mode does nothing.

i see more and more lies here!
Well, forgetting Hi Res for a moment, the true resolution of the ADC is 8 bits - so the question becomes: how do you map 256 voltage levels to 400 vertical pixels? You have to so some upsampling. I haven't examined the DS1000Z closely, but on the DS2000, Rigol maps each level to 2 pixels, so the full ADC = ~10.2 vertical divs.

BTW, new thread created here (https://www.eevblog.com/forum/testgear/anomalies-andor-bugs-inbetween-the-rigol-msods1000z-msods2000a-msods4000/new/#new).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 22, 2014, 08:36:50 pm
the true resolution of the ADC is 256 bits
lol no  :palm:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 22, 2014, 08:42:52 pm
we continued in the new thread and i already corrected that....  ;)

we SHOULD leave this thread to the jitter/trigger problems by now.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 22, 2014, 08:51:11 pm
2nd email from them this AM in response to the questions document.

"Ok. Excellent. Thank you very much for the video.

We haven't been able to reproduce the issue on units that we have here.

Would you be willing to be without the scope for a week or so?

We would like to ask if you could ship the scope to us (we will send you a FedEx label.. just need you to box it up and ship it) for further testing?

We will test it with beta firmware revisions and then ship it back once we have a solid fix in place.

WRT the 30 day return.. we are extending it until we get the fix from Engineering.. so, no risk from that standpoint"


Are you kidding me!  I have a hard time believing they have no scope to test with.  They want to use my personal scope for testing???  Seems like a mickey mouse operation.  Lets see... I purchase a new scope so they can do R&D.
I am very disappointed in the way this whole thing has been handled.  This is the last Rigol product I will purchase.

Rigol, Send me one of the working scopes you have. and I will gladly send you this broken one for R&D.  :wtf:

Rigol sent another email stating they are going to send a new working scope to exchange the broken one for use to troubleshoot these issues.   :-+ 
Jeff

Has anyone else received any communication from Rigol regarding these issues?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Dave Turner on November 22, 2014, 09:00:50 pm
Also consider that depending what else is being shown the vertical space available can be reduced. Therefore the display algorithm has to be able to map a number of different 'resolutions'.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 22, 2014, 09:06:59 pm
the true resolution of the ADC is 256 bits
lol no  :palm:

 ;D - corrected - although I'm not sure a typo constitutes a face-palming moment, but to each their own.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 22, 2014, 09:08:10 pm
we continued in the new thread and i already corrected that....  ;)

we SHOULD leave this thread to the jitter/trigger problems by now.

Thank You!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 22, 2014, 09:49:16 pm
jkrichards, stay here if you are interested in tracking the Jitter issue. It is the off-topic discussion on an unrelated subject which is branching off.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 22, 2014, 10:16:58 pm
Has anyone else received any communication from Rigol regarding these issues?

Yes, I have.  But I said I was going to post if there was any progress to report.  There hasn't been.

I've had a few exchanges with my assigned support person, but to make it short in the latest message he asked if I saw the problem on my scope specifically, and he said they've not been able to recreate the problem on their units.   He suggested I let the scope warm up and do a self-cal and he included a copy of the user guide.

I replied with a screen capture of the issue on my scope, along with the scope settings and signal input as he requested.  I also referenced the blog again and pointed out not all units have the problem.  And I pointed him to Dave's message indicating that Rigol engineering had recreated the problem and was working on a fix.

That was yesterday (11/21) in the AM.  No reply on that one yet.  There was no suggestion that I send him my scope, but he did say that my eval period would be extended if needed while they continue to investigate.


To avoid confusion for everyone, my case is *only* about the 5us jitter issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fenichel on November 22, 2014, 10:43:15 pm
  I gather from other entries on this thread that the two verified problems (5 us jitter, AC trigger coupling) appear on some DS1054Z oscilloscopes but not others.  Would it be useful to start a new, comment-free thread each of whose messages gave just the serial number of an oscilloscope, whether it had the jitter problem, and whether it had the AC-trigger problem?  For example, one or both problems might be limited to, but universal in, a certain range of serial numbers.

  I'll start it off:  Both problems are easily reproduced on #DS1ZA163655288.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 22, 2014, 10:59:04 pm
  I gather from other entries on this thread that the two verified problems (5 us jitter, AC trigger coupling) appear on some DS1054Z oscilloscopes but not others.  Would it be useful to start a new, comment-free thread each of whose messages gave just the serial number of an oscilloscope, whether it had the jitter problem, and whether it had the AC-trigger problem?  For example, one or both problems might be limited to, but universal in, a certain range of serial numbers.

  I'll start it off:  Both problems are easily reproduced on #DS1ZA163655288.

A reasonable idea, although the initial post would need to be very explicit, step by step, about exactly how to reproduce the problem. In particular, how high the frequency has to be, and how to distinguish between scope jitter and source jitter (avoiding crap PLLs and spread sprectrum sources). A few people here were expecting to see a few ns jitter on a timebase suited to the 1kHz scope calibration signal and gave false reports accordingly, others were using crap sources and their problem went away with a sensible source...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 22, 2014, 11:13:13 pm


 ;D - corrected - although I'm not sure a typo constitutes a face-palming moment, but to each their own.

typo would be '7' or '9' (or 'u', or 'i'), this way it's brain-fart.
 ;)

btw. based on rigol feedback....rigol is somewhat silly company....this should be addressed by people who can fix it, not sales folks...and in a uniform way...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 22, 2014, 11:44:55 pm


 ;D - corrected - although I'm not sure a typo constitutes a face-palming moment, but to each their own.

typo would be '7' or '9' (or 'u', or 'i'), this way it's brain-fart.
 ;)

btw. based on rigol feedback....rigol is somewhat silly company....this should be addressed by people who can fix it, not sales folks...and in a uniform way...

The Rigol representative who has been taking care of my case is an Applications Engineer.  The correspondence started as follows:

"My name is xxxxx xxxxx and I am an Applications Engineer at Rigol Technologies USA. Thank you for writing in."

They want my scope to do some test.  At first I thought it was a little weird for them to be asking me to send it in so I asked for a replacement first. He told me he will send me a brand new working unit for exchange of my unit.  So soon they will have a broken unit to do testing.  The only thing that I am still puzzled about is the fact that Dave's message stated they found the issues and will have test firmware next week that will correct theses issues without deleting any feature.   :-//
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Fenichel on November 22, 2014, 11:49:32 pm
Quote
A reasonable idea, although the initial post would need to be very explicit, step by step, about exactly how to reproduce the problem. In particular, how high the frequency has to be, and how to distinguish between scope jitter and source jitter (avoiding crap PLLs and spread sprectrum sources). A few people here were expecting to see a few ns jitter on a timebase suited to the 1kHz scope calibration signal and gave false reports accordingly, others were using crap sources and their problem went away with a sensible source...
  That's a fair comment, but at least as regards the "5 us jitter" problem, it shouldn't be too hard to describe the proper test procedure.  How about
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 12:04:40 am
Quote
A reasonable idea, although the initial post would need to be very explicit, step by step, about exactly how to reproduce the problem. In particular, how high the frequency has to be, and how to distinguish between scope jitter and source jitter (avoiding crap PLLs and spread sprectrum sources). A few people here were expecting to see a few ns jitter on a timebase suited to the 1kHz scope calibration signal and gave false reports accordingly, others were using crap sources and their problem went away with a sensible source...
  That's a fair comment, but at least as regards the "5 us jitter" problem, it shouldn't be too hard to describe the proper test procedure.  How about
  • Look at a reasonably stable multi-MHz signal.  For example, look at the crystal clock input of a convenient microcontroller.
  • Compare the apparent trace widths at no delay, 5 us delay, 10 us delay, 15 us delay, and 30 us delay.
  • If the source is unstable, you may see the apparent trace width monotonically increase with increasing delay.
  • If the reported "5 us jitter" problem is present, the trace width will be narrow at delays of 0, 10, and 30 us, but wider at delays of 5 us and 15 us.

I don't think it would be necessary to do anything past the 5us.  Seems the affected units always show jitter at 5us.

easy test I did and sent to Rigol:

1) display a 20mhz square wave using standard DC triggering.
2) move the trigger back to 5us.

If you have the jitter problem it will show.
I think keeping it simple would cut down on confusion.

To verify the generated source they could do the same test on another model scope as I did.

Also if I'm not mistaken ALL DS1000Z series scopes have the broken AC triggering issue. (not to be confused with the 5us issue)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 12:14:59 am
Also I forgot about NOT using the built in generator in models that have it as it seems this is not a good test. Use an external generator.
 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 23, 2014, 12:42:02 am
I don't think it would be necessary to do anything past the 5us.  Seems the affected units always show jitter at 5us.

easy test I did and sent to Rigol:

1) display a 20mhz square wave using standard DC triggering.
2) move the trigger back to 5us.

If you have the jitter problem it will show.
I think keeping it simple would cut down on confusion.

NO! You must test at 10us as well, because this confirms that any jitter you see at 5us isn't genuine source jitter.  Just "knowing that your source is jitter-free in your heart" isn't good enough. See, this is exactly why we need to be so explicit about these instructions.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 01:22:26 am
I don't think it would be necessary to do anything past the 5us.  Seems the affected units always show jitter at 5us.

easy test I did and sent to Rigol:

1) display a 20mhz square wave using standard DC triggering.
2) move the trigger back to 5us.

If you have the jitter problem it will show.
I think keeping it simple would cut down on confusion.

NO! You must test at 10us as well, because this confirms that any jitter you see at 5us isn't genuine source jitter.  Just "knowing that your source is jitter-free in your heart" isn't good enough. See, this is exactly why we need to be so explicit about these instructions.

Wouldn't testing with the 2nd scope of a different model be the best test of a generator?

In your quote you left this out of my post.
"To verify the generated source they could do the same test on another model scope as I did.

Also if I'm not mistaken ALL DS1000Z series scopes have the broken AC triggering issue. (not to be confused with the 5us issue)"


I agree it would be good to do the 10us also but not necessary if you have a known good signal.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on November 23, 2014, 01:38:12 am
Also if I'm not mistaken ALL DS1000Z series scopes have the broken AC triggering issue. (not to be confused with the 5us issue)"[/b]

I agree it would be good to do the 10us also but not necessary if you have a known good signal.

And what makes the best instructions for n00bs? "Also do the same at 10us." or "Please ensure you have a known good signal. You can check this by using that second scope that you obviously have. If you don't have a second scope, the following sources are considered acceptable: bla bla bla"? You're not necessarily saying anything wrong here, but you're losing sight of the goal.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 01:56:17 am
Also if I'm not mistaken ALL DS1000Z series scopes have the broken AC triggering issue. (not to be confused with the 5us issue)"[/b]

I agree it would be good to do the 10us also but not necessary if you have a known good signal.

And what makes the best instructions for n00bs? "Also do the same at 10us." or "Please ensure you have a known good signal. You can check this by using that second scope that you obviously have. If you don't have a second scope, the following sources are considered acceptable: bla bla bla"? You're not necessarily saying anything wrong here, but you're losing sight of the goal.


Just trying to keep it simple.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 02:07:36 am
  I gather from other entries on this thread that the two verified problems (5 us jitter, AC trigger coupling) appear on some DS1054Z oscilloscopes but not others.  Would it be useful to start a new, comment-free thread each of whose messages gave just the serial number of an oscilloscope, whether it had the jitter problem, and whether it had the AC-trigger problem?  For example, one or both problems might be limited to, but universal in, a certain range of serial numbers.

  I'll start it off:  Both problems are easily reproduced on #DS1ZA163655288.

I'm not sure it is a good idea to post serial numbers on an open forum.  Might be better to post purchase date, Firmware and hardware revisions.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nuno on November 23, 2014, 03:18:43 am
(...) Attached is a montage of 4 different screenshots. T=0, T=5us, T=15us and T=105us. Same 10MHz Square wave from DG4162, 50% dutycycle. Input DC coupled, trigger AC coupled. For reference, this is on a DS4k.

As you can see it does a look a bit better at T=0 and gets progressively worse as T increases (as expected). It's not much of a difference between T=0 and T=15 but it's clearly vissible at T=105us.

It looks more like intensity level feature related, because all images have actually basically the same trace width (5 pixels), but on the smaller T ones you have a stronger central trace line and that gets dimmer and dimmer with increasing T. I guess I would implement the core intensity level feature (phosphor "inertia") by setting the trace intensity to a function of its T ("older" traces get drawn dimmer)... maybe some confusion here.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 03:32:08 am
(...) Attached is a montage of 4 different screenshots. T=0, T=5us, T=15us and T=105us. Same 10MHz Square wave from DG4162, 50% dutycycle. Input DC coupled, trigger AC coupled. For reference, this is on a DS4k.

As you can see it does a look a bit better at T=0 and gets progressively worse as T increases (as expected). It's not much of a difference between T=0 and T=15 but it's clearly vissible at T=105us.

It looks more like intensity level feature related, because all images have actually basically the same trace width (5 pixels), but on the smaller T ones you have a stronger central trace line and that gets dimmer and dimmer with increasing T. I guess I would implement the core intensity level feature (phosphor "inertia") by setting the trace intensity to a function of its T ("older" traces get drawn dimmer)... maybe some confusion here.

What does this have to do with the topic here???  These off topic post make it really hard to follow the original intent.  over 2 pages of resolution jabbering and false promises to take it elsewhere.   |O  Mods.... Is there a way these OT post can be moved?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 23, 2014, 03:47:11 am
(...) Attached is a montage of 4 different screenshots. T=0, T=5us, T=15us and T=105us. Same 10MHz Square wave from DG4162, 50% dutycycle. Input DC coupled, trigger AC coupled. For reference, this is on a DS4k.

As you can see it does a look a bit better at T=0 and gets progressively worse as T increases (as expected). It's not much of a difference between T=0 and T=15 but it's clearly vissible at T=105us.

It looks more like intensity level feature related, because all images have actually basically the same trace width (5 pixels), but on the smaller T ones you have a stronger central trace line and that gets dimmer and dimmer with increasing T. I guess I would implement the core intensity level feature (phosphor "inertia") by setting the trace intensity to a function of its T ("older" traces get drawn dimmer)... maybe some confusion here.

What does this have to do with the topic here???  These off topic post make it really hard to follow the original intent.  over 2 pages of resolution jabbering and false promises to take it elsewhere.   |O  Mods.... Is there a way these OT post can be moved?

Seriously? They are discussing the jitter mentioned by Dave. Perhaps you need to relax and get to know the way this forum operates - some of the best stuff here happens perpendicular-to-topic.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 03:49:37 am
(...) Attached is a montage of 4 different screenshots. T=0, T=5us, T=15us and T=105us. Same 10MHz Square wave from DG4162, 50% dutycycle. Input DC coupled, trigger AC coupled. For reference, this is on a DS4k.

As you can see it does a look a bit better at T=0 and gets progressively worse as T increases (as expected). It's not much of a difference between T=0 and T=15 but it's clearly vissible at T=105us.

It looks more like intensity level feature related, because all images have actually basically the same trace width (5 pixels), but on the smaller T ones you have a stronger central trace line and that gets dimmer and dimmer with increasing T. I guess I would implement the core intensity level feature (phosphor "inertia") by setting the trace intensity to a function of its T ("older" traces get drawn dimmer)... maybe some confusion here.

What does this have to do with the topic here???  These off topic post make it really hard to follow the original intent.  over 2 pages of resolution jabbering and false promises to take it elsewhere.   |O  Mods.... Is there a way these OT post can be moved?

Seriously? They are discussing the jitter mentioned by Dave. Perhaps you need to relax and get to know the way this forum operates - some of the best stuff here happens perpendicular-to-topic.

How is this related to the jitter issue?  Sorry I thought this was part of the ongoing resolution discussion.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 23, 2014, 03:53:06 am
How is this related to the jitter issue?

The images are an attempt to duplicate the jitter issue on a DS4000 - another of the Rigol UltraVision DSOs which Dave doesn't own, but which I'm sure he would have tested if he had (as he did with the DS2000).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 23, 2014, 03:54:57 am
How is this related to the jitter issue?

The images are an attempt to duplicate the jitter issue on a DS4000 - another of the Rigol UltraVision DSOs which Dave doesn't own, but which I'm sure he would have tested if he had (as he did with the DS2000).


Sorry, I thought this topic was the Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems discussion.  My bad... Ill move on.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: TheBay on November 23, 2014, 03:53:52 pm
(...) Attached is a montage of 4 different screenshots. T=0, T=5us, T=15us and T=105us. Same 10MHz Square wave from DG4162, 50% dutycycle. Input DC coupled, trigger AC coupled. For reference, this is on a DS4k.

As you can see it does a look a bit better at T=0 and gets progressively worse as T increases (as expected). It's not much of a difference between T=0 and T=15 but it's clearly vissible at T=105us.

It looks more like intensity level feature related, because all images have actually basically the same trace width (5 pixels), but on the smaller T ones you have a stronger central trace line and that gets dimmer and dimmer with increasing T. I guess I would implement the core intensity level feature (phosphor "inertia") by setting the trace intensity to a function of its T ("older" traces get drawn dimmer)... maybe some confusion here.

What does this have to do with the topic here???  These off topic post make it really hard to follow the original intent.  over 2 pages of resolution jabbering and false promises to take it elsewhere.   |O  Mods.... Is there a way these OT post can be moved?

Seriously? They are discussing the jitter mentioned by Dave. Perhaps you need to relax and get to know the way this forum operates - some of the best stuff here happens perpendicular-to-topic.

Well said  :-+
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 25, 2014, 12:47:59 pm
Any update from Rigol on a fix? Some of us are approaching the 30 day return window.

If anyone out there has a bodge for the ADF4360-7 to fix the 100 KHz modulation... I'm prepared to void my warranty! ;D
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 25, 2014, 03:42:23 pm
I can build a small board with a good 1Ghz clock and mail to you. Let me check if i have any proto PCBs left, if not i will order. But lets see first what Rigol has to say this week as they promised.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MrElectro on November 25, 2014, 05:21:09 pm
I can build a small board with a good 1Ghz clock and mail to you. Let me check if i have any proto PCBs left, if not i will order. But lets see first what Rigol has to say this week as they promised.

Would this board replace / bypass the ADF4360-7 ?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 25, 2014, 05:31:13 pm
It would have its own 4360-7 IC. The one on the scope can technically be used and reprogrammed  but that would require doing some damage to the PCB traces to hijack the SPI bus. We can do a less intrusive by just unsoldering the existing two decoupling capacitors and injecting our own clock. That is what i am thinking.

Alternatively, we could remove the decoupling cap on the 25 Mhz reference line and connect an external signal gen and vary frequency a little and see if the PLL locks. If Nonorthogonal has a suitable signal gen he could try this now.

ADDED: And the indication of a lock condition would be the voltage on the 4360-7 CP pin going from sawtooth to a straight line at some level of DC. Once that is achieved, go and recheck if the 5us jitter gone.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MrElectro on November 25, 2014, 07:49:51 pm
It would have its own 4360-7 IC. The one on the scope can technically be used and reprogrammed  but that would require doing some damage to the PCB traces to hijack the SPI bus. We can do a less intrusive by just unsoldering the existing two decoupling capacitors and injecting our own clock. That is what i am thinking.

Alternatively, we could remove the decoupling cap on the 25 Mhz reference line and connect an external signal gen and vary frequency a little and see if the PLL locks. If Nonorthogonal has a suitable signal gen he could try this now.

ADDED: And the indication of a lock condition would be the voltage on the 4360-7 CP pin going from sawtooth to a straight line at some level of DC. Once that is achieved, go and recheck if the 5us jitter gone.

Could the 4360-7 be reprogrammed with a firmware update?  If Rigol doesn't come through with a fix at least we have other options.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 25, 2014, 07:55:33 pm
The IC gets initialized at power up, so should be reprogrammable via firmware updates from Rigol.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: NiHaoMike on November 25, 2014, 08:08:46 pm
Maybe use a spectrum analyzer to make sure it really is a noisy sampling clock and not a strange bug in the digital trigger?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: XFDDesign on November 25, 2014, 08:48:06 pm
Changing the component values of the loop-filter is more likely to be an easier and more effective solution -- if it's actually the PLL to begin with.

Maybe use a spectrum analyzer to make sure it really is a noisy sampling clock and not a strange bug in the digital trigger?

The SpecAn would be the best tool to look at the output of the VCO, if it didn't load down the system. As well, it would display any jitter as "phase noise." The thing is, looking at the Charge-pump/VTune pin is the easier and less invasive route. When you look at MikeL's picture (https://www.eevblog.com/forum/index.php?action=dlattach;topic=38902.0;attach=119488;image (https://www.eevblog.com/forum/index.php?action=dlattach;topic=38902.0;attach=119488;image)) you see a ramp-like behavior on a period of 10uS with a bunch of noise riding on it. The loop filter is likely running around 100kHz with a 10MHz PFD frequency. The integrating nature of the '4360's VCO is doubtful to be slow enough to "neglect" the noise on the CP and average it out. Redesign the loop-filter for something slower, and you will likely see the whole system clean up.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 26, 2014, 03:34:17 pm
It would have its own 4360-7 IC. The one on the scope can technically be used and reprogrammed  but that would require doing some damage to the PCB traces to hijack the SPI bus. We can do a less intrusive by just unsoldering the existing two decoupling capacitors and injecting our own clock. That is what i am thinking.

Alternatively, we could remove the decoupling cap on the 25 Mhz reference line and connect an external signal gen and vary frequency a little and see if the PLL locks. If Nonorthogonal has a suitable signal gen he could try this now.

ADDED: And the indication of a lock condition would be the voltage on the 4360-7 CP pin going from sawtooth to a straight line at some level of DC. Once that is achieved, go and recheck if the 5us jitter gone.

If the on-board 4360-7 is to be replaced with something else, it should be verified that Rigol is not programming any other frequency into it when other sweep speeds are selected.  Since the part is only spec'd for 350MHz to 1800MHz, the only other option would be 500MHz to fit nicely into the ADC and sweep selection.

I think it's highly unlikely they're changing the frequency anyway, but it's not beyond possibility.

For me, I'm going to wait to see what Rigol comes up with.  No word yet.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 26, 2014, 04:35:54 pm
The purpose of the test is to see if this is indeed what is causing the 5uS screaming issue. Other modes can be checked too, including AC trigger coupling but that is secondary. Rigol will need to fix that one first and anyway.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 26, 2014, 04:41:30 pm
Maybe use a spectrum analyzer to make sure it really is a noisy sampling clock and not a strange bug in the digital trigger?

Good idea. Please see page 19 of this thread.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 26, 2014, 04:58:33 pm
MarkL,
Can you measure all or any of this:

25Mhz oscillator frequency
Loop filter component values
PLL programming data at power up

We could plug it in to the simulator and see if makes sense
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on November 26, 2014, 05:12:31 pm
The purpose of the test is to see if this is indeed what is causing the 5uS screaming issue.
I guess I lost track that this was just for a test and not for a fix that was being proposed.  My bad.

MarkL,
Can you measure all or any of this:

25Mhz oscillator frequency
Loop filter component values
PLL programming data at power up

We could plug it in to the simulator and see if makes sense

I can but I'm out traveling for the holiday (US Thanksgiving) for the rest of the week.  I can do it when I get back early next week if Rigol still has no response.  It's going to take a little more disassembly since the loop filter components are on the underside.  I haven't gone that far yet.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 26, 2014, 06:45:48 pm
Thanks MarkL. I can actually see in the board level photos the two loop filter resistors marked 55B and 93A, a search on smt resistor marking resulted in 3.65K and 909 Ohm. And two out of the three capacitors could probably be measured by simply measuring the capacitance from pins CP and Tune to ground. So just one unknown will be left if do not want to disassemble the scope.


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 26, 2014, 08:32:42 pm
I received an email from Rigol this AM.  They are testing the beta firmware now and should release it soon.  They have been very responsive to these issues.  I take back my comment about not purchasing another Rigol product as it turns out they proved to have excellent customer service.  Remember this issue was discovered only a week or so ago and will most likely have it fixed this week.  :clap:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 26, 2014, 09:21:41 pm
Didn't people say AC trigger coupling problem was reported 2 years ago?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: dr.diesel on November 26, 2014, 09:30:05 pm
have excellent customer service.

Only because it was reveled on one of Dave's videos.  The forum has many examples of Rigol completely ignoring issues and problems. 

I and many others have contacted Rigol with dozens of issues on the 4000 series and have been completely ignored for almost a full year now.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on November 26, 2014, 09:35:39 pm
Customer service often require "a little push". Loss of sales will get the fastest action.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 26, 2014, 10:03:14 pm
have excellent customer service.

Only because it was reveled on one of Dave's videos.  The forum has many examples of Rigol completely ignoring issues and problems. 

I and many others have contacted Rigol with dozens of issues on the 4000 series and have been completely ignored for almost a full year now.

I think he just revealed the AC triggering issue in the same video.  Maybe that will be fixed in the 4000 also.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Hydrawerk on November 26, 2014, 10:35:17 pm
It is funny that there are bugs in DS4000 series while this is an expensive scope with good hardware that is not intended for hobbyists.  :(
And it was released in January 2012 or so (?).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 26, 2014, 10:48:55 pm
That is why i called them a mickey mouse company, i. e. not serious. I think i saw someone saying they worked for Agilent. Well may be, but i think it was Agilent who was in charge of the quality control part of the house.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RigolTechUSA on November 26, 2014, 11:32:47 pm
Rigol has created updated firmware for the MSO1000Z and DS1000Z series of scopes in immediate response to the issues found by Dave and the EEVBlog community.

   Firmware has passed the engineering and applications tests and is proceeding to the full suite of testing to go into production. We expect the final firmware for the MSO1000Z and DS1000Z series to be released by December 19th with the MSO2000A, DS2000A, and DS2000 firmware to follow and to be available by toward the end of December. The final releases will be accompanied by complete release notes, but in the spirit of our partnership with EEVBlog we wanted to make our DS1000Z customers who are seeing problems or are concerned about these issues to have immediate availability of the beta firmware. This beta firmware comes with the usual beta warnings. In our initial testing we have found no issue upgrading or loading these firmware files, but as with all beta code you load this at your own risk with the possibility that your oscilloscope may not work correctly. Rigol will support you as we can once a final release is available, but there is always a possibility of a serious or unrecoverable issue. Any customers at all concerned about this possibility should wait for the final release, but for our friends at EEVBlog we wanted to make the beta firmware immediately available for those who would like it.
You can download the beta MSO1000Z and DS1000Z firmware here: http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-0576/1/-/-/-/-/DS1000ZUpdate.zip (http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-0576/1/-/-/-/-/DS1000ZUpdate.zip)

To update, please follow these instructions:
1)  Choose a USB memory stick that is recognized by the Scope. When the USB stick is inserted into the USB connection at the front of the scope, the scope should show a USB device detected.
2) Download the DS1000ZUpdate.GEL file. Extract it from the zip file to the primary partition of the USB stick.
3) When the USB stick is inserted, the scope should detect the new firmware and offer a firmware upgrade option.
Confirm that you wish to upgrade and the scope should then upgrade the firmware.
4) Make certain that the power and the USB drive are not disturbed or disconnected during the upgrade process.
5) When complete the DS1000Z will prompt you that the upgrade was successful and ask you to reboot using the front power button.

Lastly, if anyone has questions or concerns they want to discuss with us, we are always here. Contact your local Rigol office or distribution partner. Our USA number is 877-4-RIGOL-1. Every DS1000Z bought in the USA is under our 3 year warranty program and Rigol quality is important to us all over the world.

Thanks,

Chris Armstrong
Director of Product Marketing & SW Applications
Rigol Technologies
10200 SW Allen Blvd.  Suite C
Beaverton, OR 97005
office/fax: 877-4-RIGOL-1
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 26, 2014, 11:38:50 pm
Thank You Rigol and Chris Armstrong!   :-+  Is it possible to get the latest firmware in case we would need to go back?  Would this be possible as past firmware would not allow this.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xnaron on November 27, 2014, 03:04:23 am
Wow...the silence is deafening... I would have thought there would be a bunch of posts by now on whether the new firmware fixed the issues.  I would test but don't have a signal generator.  Anyone?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 27, 2014, 03:28:57 am
IT'S FIXED!!

Chris, you're awesome!! Don't listen to the haters on Internet forums, you're doing terrific work!!  :)

Everyone have a Happy Thanksgiving (US) with your fixed Rigol scope.

(http://i.imgur.com/TEO5ASB.png)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 03:53:14 am
IT'S FIXED!!

SWCHEEET!   :scared:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sawmilkd on November 27, 2014, 04:13:46 am
First time poster. Read through the entire thread tonight, verified both issues (5us jitter, ac trigger coupling). Testing new firmware. Verified it fixed these issues.

Test setup:
Scope: DS1054Z (unlocked all options)
Probe: As delivered Rigol probe, 1X configuration, compensated via test signal square wave
Reference Clock for Test: 20MHz can oscillator on breadboard. Driven at 3.3V.

Original configuration, DC coupled input, DC coupled trigger, no trigger offset:
(http://i.imgur.com/63Kg543.png)

Original configuration, DC coupled input, DC coupled trigger, 5us trigger offset:
(http://i.imgur.com/aMOeFoa.png)

Original configuration, DC coupled input,AC coupled trigger (0V), 0us trigger offset:
(http://i.imgur.com/WF1G8CN.png)

** AFTER BETA FIRMWARE UPDATE **

S/W 00.04.02.SP3, DC coupled input, DC coupled trigger, no trigger offset:
(http://i.imgur.com/kMRXRhW.png)

S/W 00.04.02.SP3, DC coupled input, DC coupled trigger, 5us trigger offset:
(http://i.imgur.com/hl7uFqy.png)

S/W 00.04.02.SP3, DC coupled input,AC coupled trigger (0V), 0us trigger offset:
(http://i.imgur.com/CBmFnkr.png)

Sorry the V/div and us/div are not consistent. I was excited to see everything working and didn't keep notes between screen grabs!
After the firmware update, all of my options remain unlocked, for those who suffered through entering all of those keys!

**UPDATE THIS AM**
None of the buttons work if I power up the oscilloscope without the USB stick used to flash the scope installed. If I power cycle with the USB stick in, I hear a "beep" on power up (normally quiet as I have sound disabled). Then the message box appears to update firmware with the same version on the USB stick. I select cancel, and everything works fine after that. Very odd. I can also confirm that the software version shown in the System panel is not updating after the flash.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on November 27, 2014, 04:40:41 am
Forgive my ignorance, what is the squarewave 20 MHz indicator on screen after the firmware update?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 27, 2014, 04:45:13 am
OK sounds good. So when MarkL is back from holidays hopefully he can re-measure the 4360-7 PLL and if it now operates properly than it was the root cause of the problem.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 05:29:05 am
Forgive my ignorance, what is the squarewave 20 MHz indicator on screen after the firmware update?

That is an existing measure option you can turn on, always been there.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on November 27, 2014, 05:34:29 am
Forgive my ignorance, what is the squarewave 20 MHz indicator on screen after the firmware update?

That is an existing measure option you can turn on, always been there.
On-screen Frequency counter....right. Thanks
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on November 27, 2014, 05:36:48 am
I can just about smell a quick eevblog followup video.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on November 27, 2014, 05:55:42 am
I can just about smell a quick eevblog followup video.
Quote
This beta firmware comes with the usual beta warnings.
We expect the final firmware for the MSO1000Z and DS1000Z series to be released by December 19th
Wouldn't it be prudent to ensure any fix is widespread first?
And no longer a Beta version?
You wouldn't want to see a repeat of a recent Siglent firmware blunder.  :palm:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on November 27, 2014, 06:04:39 am
I think it would be a time will tell video, as it should be.

To be honest I wouldn't put beta firmware out.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on November 27, 2014, 08:13:19 am
I tried the beta firmware and I want to make it clear that you need to beware.

At first I applied the procedure detailed by Chris in this post
https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg558457/#msg558457 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg558457/#msg558457)

And after a reboot it did not change the firmware reported by showing the system info, it remains at 00.04.02.03.SP3
and not 00.04.02.03.09.

Of course it did not fix the 5us jitter issue. It made it worse.

See the below images, using the latest BETA firmware.
I add two images using my DS2072 DSO input the same signal, via same cable, 50 ohm termination etc
to illustrate the signal has no jitter.
Check out
https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg553033/#msg553033 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg553033/#msg553033)
for more from my DS1054Z before the beta firmware.

The state that my DSO was in may be important. I had applied the option code to make all options permanent
and so the DSO thought it was a DS1104Z when the firmware was updated.
This was a mistake it seems.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 10:48:30 am
Rigol has created updated firmware for the MSO1000Z and DS1000Z series of scopes in immediate response to the issues found by Dave and the EEVBlog community.

Lastly, if anyone has questions or concerns they want to discuss with us, we are always here. Contact your local Rigol office or distribution partner. Our USA number is 877-4-RIGOL-1. Every DS1000Z bought in the USA is under our 3 year warranty program and Rigol quality is important to us all over the world.

Thanks,

Chris Armstrong
Director of Product Marketing & SW Applications
Rigol Technologies
10200 SW Allen Blvd.  Suite C
Beaverton, OR 97005
office/fax: 877-4-RIGOL-1

@Chris Armstrong - Firstly, thanks to Rigol for addressing and responding to this issue in terms of the 1000Z series. I applied the fix and it works fine on the MSO1074Z I have.

Two questions:

1) Can owners of the DS2000(A) expect a similar fix soon? The AC-coupled trigger-jitter and offset problems were reported to Rigol USA about a year and a half ago.

2) Since Rigol is in a jitter-fixing mode, could they perhaps also tackle the issue of the 8ns jitter on the Trigger Output? This bug makes the use of the Trigger Output problematic at best, and was first noticed on the DS2000 and reported about 2 years ago. It is also present on all of the MSO/DS1000Z models, as shown in my attached image (Channel 3 is the Trigger Output fed back into the DSO displaying the ~8ns of jitter).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 11:19:19 am
4.43GV/s sounds impressive ;p
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 02:31:27 pm
I applied the fix and it works fine on the MSO1074Z I have.

I did too, but as the other person said, the version says SP3, and every time it still detects the update file. Is this correct behavior?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 02:36:30 pm
I applied the fix and it works fine on the MSO1074Z I have.

I did too, but as the other person said, the version says SP3, and every time it still detects the update file. Is this correct behavior?

Yes.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 02:42:25 pm
I applied the fix and it works fine on the MSO1074Z I have.

I did too, but as the other person said, the version says SP3, and every time it still detects the update file. Is this correct behavior?

Yes.

Thanks :)

I dont have a good source to test, but I seems similar to poida_pie's screens. :(

Going to let it warm up a bit and try calibration.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 02:54:15 pm
Just checked my previous captures. 125MHz crystal.

Previously, no jitter at 10us, now just jitter all over the place.

At 250ns, the jitter looks identical, so it seems it just gets worse progressively with no improvement after 5us as previously.

So maybe the update helps some units, but not for others...   :'(

Does someone have a copy of the previous firmware? If so, can you post it please.

From the previous firmware, no jitter at 10us
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=120825;image)

New (beta) firmware, just a mess...
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=120829;image)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 03:34:15 pm
Previously, no jitter at 10us, now just jitter all over the place.

First of all, you should perhaps specify exactly what it is you are testing. In your images, it shows the input channel as AC-coupled. The two reported bugs were jitter with DC-coupling of channel at 5us - and jitter of anAC-coupled trigger.

To avoid the spread of misinformation: if people are having problems with this BETA FW - they should probably specify precisely what they are doing and with what input source.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 03:38:46 pm
Previously, no jitter at 10us, now just jitter all over the place.

First of all, you should perhaps specify exactly what it is you are testing. In your images, it shows the input channel as AC-coupled. The two reported bugs were jitter with DC-coupling of channel at 5us - and jitter with AC-coupling of trigger.

To avoid the spread of misinformation: if people are having problems with this BETA FW - they should probably specify precisely what they are doing and with what input source.

This is for the 5us jitter issue, where multiples of 10us was jitter free previously (well up to a point).

Does it really matter how the input is coupled? I just faithfully recreated what I did previously (yes, the amplitude is slightly more, missed that ;p). The channel is using DC coupled trigger (if would show no offset marker if it was AC coupled trigger), and it shows at 10us the trigger was working without jitter. Input source is a 125MHz crystal as mentioned.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sawmilkd on November 27, 2014, 03:45:04 pm
I just updated my previous post regarding the beta firmware patch w/ a potential big issue. I have a DS1054Z, board version 0.1.1. Upon powering up this AM, everything "seemed" to be working fine (visibly triggering on my 20MHz test oscillator circuit from yesterday). However, none of the front panel buttons or knobs have any effect. They are all dead. Power cycling had no effect. The only way I was able to get control was to plug back in the USB stick I used last night to flash the new firmware BEFORE powering on the DS1054Z. The startup sequence was slightly different (a beep was present that is not normally there). After initialization, the firmware update box is presented (though it says it's the same version that's installed, but not the same version shown on the System information display). If I select cancel, the dialog box goes away, and the scope can be operated normally.

My DS1054Z is 100MHz unlocked. Perhaps there is a model mismatch causing trouble? Maybe Rigol was serious regarding beta status....

Anyone else experiencing this issue?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 03:48:50 pm
I just updated my previous post regarding the beta firmware patch w/ a potential big issue. I have a DS1054Z, board version 0.1.1. Upon powering up this AM, everything "seemed" to be working fine (visibly triggering on my 20MHz test oscillator circuit from yesterday). However, none of the front panel buttons or knobs have any effect. They are all dead. Power cycling had no effect. The only way I was able to get control was to plug back in the USB stick I used last night to flash the new firmware BEFORE powering on the DS1054Z. The startup sequence was slightly different (a beep was present that is not normally there). After initialization, the firmware update box is presented (though it says it's the same version that's installed, but not the same version shown on the System information display). If I select cancel, the dialog box goes away, and the scope can be operated normally.

My DS1054Z is 100MHz unlocked. Perhaps there is a model mismatch causing trouble? Maybe Rigol was serious regarding beta status....

Anyone else experiencing this issue?

Yes, had the same. Also a lock up as you said after calibration. Restart fixed it. I think the beep means it has done a firmware update (I did it twice to be sure, happened both times).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 03:52:07 pm
Does it really matter how the input is coupled? I just faithfully recreated what I did previously

The point is that you didn't faithfully recreate what Dave did - or how the bug was reported. Perhaps you've discovered a different bug - or a related one that has yet to be fixed - but it's not the conditions of the original bug.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sawmilkd on November 27, 2014, 03:53:57 pm
I just updated my previous post regarding the beta firmware patch w/ a potential big issue. I have a DS1054Z, board version 0.1.1. Upon powering up this AM, everything "seemed" to be working fine (visibly triggering on my 20MHz test oscillator circuit from yesterday). However, none of the front panel buttons or knobs have any effect. They are all dead. Power cycling had no effect. The only way I was able to get control was to plug back in the USB stick I used last night to flash the new firmware BEFORE powering on the DS1054Z. The startup sequence was slightly different (a beep was present that is not normally there). After initialization, the firmware update box is presented (though it says it's the same version that's installed, but not the same version shown on the System information display). If I select cancel, the dialog box goes away, and the scope can be operated normally.

My DS1054Z is 100MHz unlocked. Perhaps there is a model mismatch causing trouble? Maybe Rigol was serious regarding beta status....

Anyone else experiencing this issue?

Yes, had the same. Also a lock up as you said after calibration. Restart fixed it. I think the beep means it has done a firmware update (I did it twice to be sure, happened both times).

Sorry, are you saying that your scope works now without requiring the USB stick to be inserted? Seems mine requires it always at this point.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 04:05:02 pm
Does it really matter how the input is coupled? ...Input source is a 125MHz crystal as mentioned.

BTW, just checked on my DS2000 and, yes, it can matter whether a crystal is DC or AC-coupled to the channel input.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sawmilkd on November 27, 2014, 04:08:14 pm
I just updated my previous post regarding the beta firmware patch w/ a potential big issue. I have a DS1054Z, board version 0.1.1. Upon powering up this AM, everything "seemed" to be working fine (visibly triggering on my 20MHz test oscillator circuit from yesterday). However, none of the front panel buttons or knobs have any effect. They are all dead. Power cycling had no effect. The only way I was able to get control was to plug back in the USB stick I used last night to flash the new firmware BEFORE powering on the DS1054Z. The startup sequence was slightly different (a beep was present that is not normally there). After initialization, the firmware update box is presented (though it says it's the same version that's installed, but not the same version shown on the System information display). If I select cancel, the dialog box goes away, and the scope can be operated normally.

My DS1054Z is 100MHz unlocked. Perhaps there is a model mismatch causing trouble? Maybe Rigol was serious regarding beta status....

Anyone else experiencing this issue?

Yes, had the same. Also a lock up as you said after calibration. Restart fixed it. I think the beep means it has done a firmware update (I did it twice to be sure, happened both times).

Just did some power cycling testing. It appears that the scope does not respond to front panel input every other power cycle. I turned the scope off and on 10 times. Each time it alternated between responsive and non-responsive. Very strange indeed.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 04:09:31 pm
Just did some power cycling testing. It appears that the scope does not respond to front panel input every other power cycle. I turned the scope off and on 10 times. Each time it alternated between responsive and non-responsive. Very strange indeed.

Did you try clearing FRAM at bootup?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 04:13:42 pm
I just updated my previous post regarding the beta firmware patch w/ a potential big issue. I have a DS1054Z, board version 0.1.1. Upon powering up this AM, everything "seemed" to be working fine (visibly triggering on my 20MHz test oscillator circuit from yesterday). However, none of the front panel buttons or knobs have any effect. They are all dead. Power cycling had no effect. The only way I was able to get control was to plug back in the USB stick I used last night to flash the new firmware BEFORE powering on the DS1054Z. The startup sequence was slightly different (a beep was present that is not normally there). After initialization, the firmware update box is presented (though it says it's the same version that's installed, but not the same version shown on the System information display). If I select cancel, the dialog box goes away, and the scope can be operated normally.

My DS1054Z is 100MHz unlocked. Perhaps there is a model mismatch causing trouble? Maybe Rigol was serious regarding beta status....

Anyone else experiencing this issue?

Yes, had the same. Also a lock up as you said after calibration. Restart fixed it. I think the beep means it has done a firmware update (I did it twice to be sure, happened both times).

Sorry, are you saying that your scope works now without requiring the USB stick to be inserted? Seems mine requires it always at this point.

Nope, just saw the same thing. Just locks up if you start without USB :(
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 04:17:35 pm
Does it really matter how the input is coupled? I just faithfully recreated what I did previously

The point is that you didn't faithfully recreate what Dave did - or how the bug was reported. Perhaps you've discovered a different bug - or a related one that has yet to be fixed - but it's not the conditions of the original bug.

Here you go.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 04:20:42 pm
Does it really matter how the input is coupled? I just faithfully recreated what I did previously

The point is that you didn't faithfully recreate what Dave did - or how the bug was reported. Perhaps you've discovered a different bug - or a related one that has yet to be fixed - but it's not the conditions of the original bug.

Here you go.

Thanks. Hopefully it will help them track down the problem with consistent conditions.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nuno on November 27, 2014, 04:45:11 pm
I think they should open all or most of the firmware and let the community fix it and improve it, they would sell many more units and mostly get rid of software support, supporting only an official simple version which noone would use anyway. I would pay more for such an "open" unit.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sawmilkd on November 27, 2014, 04:46:23 pm
Just did some power cycling testing. It appears that the scope does not respond to front panel input every other power cycle. I turned the scope off and on 10 times. Each time it alternated between responsive and non-responsive. Very strange indeed.

Did you try clearing FRAM at bootup?

Just tried. Still seems to alternate between power cycles.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: DarkLight on November 27, 2014, 04:50:12 pm

It's Fixed for me too with 00.04.02.03.SP3

DS1074Z-S
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 04:52:11 pm
Just tried. Still seems to alternate between power cycles.

Strange; I don't have this issue at all on my MSO1074Z. Works fine without the USB stick. Perhaps it's a DS1054Z-only problem?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 05:01:15 pm
Just tried. Still seems to alternate between power cycles.

Strange; I don't have this issue at all on my MSO1074Z. Works fine without the USB stick. Perhaps it's a DS1054Z-only problem?

I am getting the semi-alternating lockup too. About 1 in 3-4 boots.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 05:05:10 pm
I am getting the semi-alternating lockup too. About 1 in 3-4 boots.

This might be meaningful if we knew what model you have.  ;)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 05:07:29 pm
It seems the interval is now ~33us, instead of 10us as previously. Model is DS1054Z (unlocked).

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=120869;image)

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=120871;image)

And jitter around the 'midpoint' ~17us

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=120889;image)

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 05:22:31 pm
It seems the interval is now ~33us, instead of 10us as previously. Model is DS1054Z (unlocked).

So it appears all of the people that have reported issues with the Beta FW so far have been using DS1054Zs with non-standard bandwidth settings.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on November 27, 2014, 06:11:06 pm
It seems the interval is now ~33us, instead of 10us as previously. Model is DS1054Z (unlocked).

So it appears all of the people that have reported issues with the Beta FW so far have been using DS1054Zs with non-standard bandwidth settings.

Non-standard, as in unlocked? Stupid question, how do I 'lock' it again? I dont mind, the bandwidth boost is merely convenient, I have a 200MHz TDS360. ;p 8MHz signal should not make any difference when 'stock'.

For anyone else who feels the beta firmware is not working, can they try increase the delay to see if they get it 'jitter free' at a much higher value than 10us?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xnaron on November 27, 2014, 06:25:04 pm
It seems the interval is now ~33us, instead of 10us as previously. Model is DS1054Z (unlocked).

So it appears all of the people that have reported issues with the Beta FW so far have been using DS1054Zs with non-standard bandwidth settings.

Non-standard, as in unlocked? Stupid question, how do I 'lock' it again? I dont mind, the bandwidth boost is merely convenient, I have a 200MHz TDS360. ;p 8MHz signal should not make any difference when 'stock'.

For anyone else who feels the beta firmware is not working, can they try increase the delay to see if they get it 'jitter free' at a much higher value than 10us?

https://www.eevblog.com/forum/testgear/ds1000z-serie-unlocking/msg531698/#msg531698 (https://www.eevblog.com/forum/testgear/ds1000z-serie-unlocking/msg531698/#msg531698)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 27, 2014, 06:32:46 pm
Non-standard, as in unlocked? Stupid question, how do I 'lock' it again? I dont mind, the bandwidth boost is merely convenient, I have a 200MHz TDS360. ;p 8MHz signal should not make any difference when 'stock'.

There is no 'unlocked' - only stock. Rigol doesn't sell bandwidth upgrades (as they do the other options) - the exploit that is used by people is an unsupported and unused (officially) piece of FW code.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: 2A03 on November 27, 2014, 07:57:04 pm
I'm using MSO1104Z (hardware version 2.1.1).
I tried 00.04.02.SP3 beta firmware.

signal source is 25MHz crystal oscillator.

1) AC coupled trigger
was fixed.(maybe)

2) jitter problems.
doesn't fix issue.(It isn't related to coupled type or trigger mode.)

:(
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 27, 2014, 08:02:12 pm
It seems the interval is now ~33us, instead of 10us as previously. Model is DS1054Z (unlocked).

So it appears all of the people that have reported issues with the Beta FW so far have been using DS1054Zs with non-standard bandwidth settings.

Non-standard, as in unlocked? Stupid question, how do I 'lock' it again? I dont mind, the bandwidth boost is merely convenient, I have a 200MHz TDS360. ;p 8MHz signal should not make any difference when 'stock'.

For anyone else who feels the beta firmware is not working, can they try increase the delay to see if they get it 'jitter free' at a much higher value than 10us?

You can remove all options:
Just go to the UltraSigma Utility, send SCPI command
:SYSTem:OPTion:UNINSTall
and reboot the scope.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Gilberto60 on November 27, 2014, 08:31:26 pm
I use Rigol ds1104Z (software version 00.02.03.Sp5) and I see the problem of AC trigger.
If I change the mode of acquisition in "Average" the problem disappears
I attach some pictures
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on November 27, 2014, 08:36:48 pm
It seems the interval is now ~33us, instead of 10us as previously. Model is DS1054Z (unlocked).

So it appears all of the people that have reported issues with the Beta FW so far have been using DS1054Zs with non-standard bandwidth settings.


Not any more.

I just installed the Beta FW on an unmolested DS1054Z (pretty much straight out of the box) and it has the dead keypad every other restart problem.  FWIW, I tried flashing a second time and no difference.

Edit: It is worse than that.  Sometimes, the keypad is dead, sometimes it works and sometimes it acts like random keys are being pressed.

The 5uS jitter does appear to be fixed.  I haven't yet tried the AC trigger coupling.

Edit: AC trigger coupling works when the keypad works.


Orin.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mamalala on November 27, 2014, 10:30:24 pm
I also have to revise my earlier post. While the jitter problem and the AC trigger problem is gone, i also have the keyboard not working on some power-ups. Most of the time it works, but every 3rd or 4th time it doesn't. Didn't notice that before because it worked after the restart, and i didn't try another restart after that.

Greetings,

Chris
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Howardlong on November 27, 2014, 10:49:58 pm
Same here, keyboard and knobs don't work about 1 in 3 times after boot, needs an off/on cycle to fix.

The AC coupled trigger problem is fixed though, and I never had the other fault.

The unit here is an MSO1074Z-S.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on November 28, 2014, 01:13:32 am
I started another thread in the Test Equipment forum.  In summary, my advice is:

Do not install the beta firmware!

It can cause your keyboard to stop working or act as if keys are being pressed randomly.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on November 28, 2014, 01:17:48 am
I started another thread in the Test Equipment forum.  In summary, my advice is:

Do not install the beta firmware!

It can cause your keyboard to stop working or act as if keys are being pressed randomly.

Sure glad this isn't a power supply  ???
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on November 28, 2014, 01:35:03 am
Does anybody have access to the orginal firmware for the DS1054Z, that is,
the version prior to the beta?

I would like to try to use this to fix the keyboard/knob zero response problem if possible.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 28, 2014, 02:20:04 am
Does anybody have access to the orginal firmware for the DS1054Z, that is,
the version prior to the beta?

I would like to try to use this to fix the keyboard/knob zero response problem if possible.

This is why I asked this question to Chris @ Rigol right after the beta firmware post.  I would not install any beta software unless we could go back to the working firmware.  Hopefully they will have this fixed soon as they promised but until then I think the original latest working firmware should be posted for download so the ones who tested can get back to where they were.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Nonorthogonal on November 28, 2014, 02:47:13 am
I started another thread in the Test Equipment forum.  In summary, my advice is:

Do not install the beta firmware!

It can cause your keyboard to stop working or act as if keys are being pressed randomly.

My keys do that occasionally, but it isn't random for me. It just waits a minute or two and then the presses that were queued up are executed at once.

I'm curious what their fix was. This seems like a bug in the GUI or Linux side (this thing runs Linux right??) and unrelated to the 5 us bug.

I wouldn't say don't install it, just be "patient" with your knob twists. The scope is off getting a cup of coffee.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on November 28, 2014, 03:38:21 am
I started another thread in the Test Equipment forum.  In summary, my advice is:

Do not install the beta firmware!

It can cause your keyboard to stop working or act as if keys are being pressed randomly.

My keys do that occasionally, but it isn't random for me. It just waits a minute or two and then the presses that were queued up are executed at once.

I'm curious what their fix was. This seems like a bug in the GUI or Linux side (this thing runs Linux right??) and unrelated to the 5 us bug.

I wouldn't say don't install it, just be "patient" with your knob twists. The scope is off getting a cup of coffee.


No.  That is not the effect I'm seeing.  It's not queueing keys, it's acting as if keys that have not been pressed are being pressed.  For example, all the measurement functions on the left light,  help screens display and all I did was press the Clear key once.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Howardlong on November 28, 2014, 09:22:01 am
I started another thread in the Test Equipment forum.  In summary, my advice is:

Do not install the beta firmware!

It can cause your keyboard to stop working or act as if keys are being pressed randomly.

My keys do that occasionally, but it isn't random for me. It just waits a minute or two and then the presses that were queued up are executed at once.

I'm curious what their fix was. This seems like a bug in the GUI or Linux side (this thing runs Linux right??) and unrelated to the 5 us bug.

I wouldn't say don't install it, just be "patient" with your knob twists. The scope is off getting a cup of coffee.

Nope, this is right after switching on, the option splash screen comes up and usually I press Clear at this point to remove the splash screen. No keys work at all. If you wait for the option splash screen to disappear, still the same, no response from any keys. I set the scope to reset back to "default" settings rather than "last" too in case that was the problem, but it made no difference.

Even after going away for an exceptionally long coffee, lunch, dinner, a long holiday, still no response, it needs a power cycle to resolve.

Edit to add: the unit itself is not locked up, there is stuff going on on the screen itself.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on November 28, 2014, 06:59:16 pm
Does anybody have access to the orginal firmware for the DS1054Z, that is,
the version prior to the beta?

I would like to try to use this to fix the keyboard/knob zero response problem if possible.

This is why I asked this question to Chris @ Rigol right after the beta firmware post.  I would not install any beta software unless we could go back to the working firmware.  Hopefully they will have this fixed soon as they promised but until then I think the original latest working firmware should be posted for download so the ones who tested can get back to where they were.


I agree that they should provide working firmware that we can go back to.  All they need to do is take the shipping firmware and change the version number such that the scope will accept it.

At the point that I installed it, there hadn't been any reports of problems on 'unmodified' scopes.  I should have waited longer.

The keypad problem is exactly the soft of problem that a beta test is meant to find.  I can't fault Rigol for making it available.  I would have thought they would have found the keyboard problems before releasing the beta FW given the number of reports here, but I would doubt that their R&D dept.  are using current off the production line units and it may be related to a particular batch.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 28, 2014, 08:47:50 pm
I think they should open all or most of the firmware and let the community fix it and improve it, they would sell many more units and mostly get rid of software support, supporting only an official simple version which noone would use anyway. I would pay more for such an "open" unit.

rather good idea, and esp. knowing that less (if any) of that code could be copyrighted by somebody else other than rigol....
 :-+

otoh i'm not sure if community already concluded it's a hardware problem...hehe...but it kinda looked that way...so the report by leppie that the offset just changed (and is not removed) is kinda interesting.

i'm still incredibly far away from applying this beta....i would be a (best) beta  tester (ever!) if somebody would pay me...and buy me a scope to test it on!  ;D
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sawmilkd on November 28, 2014, 10:38:23 pm
Here is my summary of what I'm seeing w/ the beta firmware on a DS1054Z (unlocked). This post provides some clarity regarding some of my previous observations, as well as what I've seen in other posts.

 #1: Start-up issue. This does seem random. Yesterday I thought it alternated, but now it seems to be random. It also does not matter if the USB stick w/ the firmware update is installed or not at power up. I have had the panel freeze in both cases. On a power up where the panel freezes, the scope continues to operate based upon its current settings. If I disconnect the probe, the trace disappears on the display, and the trigger stops (in normal mode). When I reconnect the probe, triggering continues, and the trace appears on the display. This indicates that the scope is not "locked up" per se, but it no longer responds to panel input.

 #2: Perceived random button press issue. This is a variant of #1. I have seen this as well. As soon as I adjust anything on the scope after power up, it acts as though I am pressing buttons randomly in rapid succession. My scope usually ends up on the help display, and then no longer responds to input. Power cycling resolves the issue.

 #3: Trigger offset jitter issue (5us/10us, or 33us, etc). The firmware patch, at least for my hardware version 0.1.1, seems to fix the offset jitter entirely. I have tried to varying the trigger offset from 0,5,10,20,33, and 50us, and I see no trigger jitter. Others claim their scope jitter now appears at something other than the previously observed 5us. I cannot recreate this.  I've attached my screenshots for these cases.

In short, this firmware update fixes all of the tigger issues from my perspective (AC trigger, AC/DC trigger offset). However, it brings with it a new issue of the front panel not responding.  It is worth mentioning that I have not experience a time where the scope was working and then locks up. It is either one or the other upon power up.

Attached are my screen shots testing the trigger offset jitter at various delay offsets, tested with a 20MHz can oscillator, 1X scope probe (Rigol) calibrated.
(http://i.imgur.com/IBt37uV.png)
(http://i.imgur.com/aHsr3W6.png)
(http://i.imgur.com/8SoGll4.png)
(http://i.imgur.com/j68yaJC.png)
(http://i.imgur.com/FxBB92n.png)
(http://i.imgur.com/7ze8A4j.png)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 28, 2014, 11:26:51 pm
sawmilkd,
Does yours self calibrate ?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sawmilkd on November 29, 2014, 12:36:08 am
sawmilkd,
Does yours self calibrate ?
I started one after reading your post. It just completed successfully.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on November 29, 2014, 12:53:53 am
sawmilkd,
Does yours self calibrate ?
I started one after reading your post. It just completed successfully.


Mine did too.  Didn't help with the keyboard problems, not that I expected it to.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: i4004 on November 29, 2014, 07:51:57 am


 #2: Perceived random button press issue. This is a variant of #1. I have seen this as well. As soon as I adjust anything on the scope after power up, it acts as though I am pressing buttons randomly in rapid succession. My scope usually ends up on the help display, and then no longer responds to input. Power cycling resolves the issue.



first of all i dunno why do you all call it "unlocked" when there should be a legal way to unlock it (by paying to rigol, was that the idea behind those locked options?) while infact it's hacked.
so call it hacked.

2nd, just yesterday i got what you explain in point2 above, but not that extreme....i turned it on, and "it" pressed 'REF' button (sure as hell i'm not pressing it) and the help screen appeared....then i hit 'help' few times and it continued to operate, i didn't do reboot.

this is just hacked 1054z, this beta firmware you're discussing was not applied.
and it will not be applied unless benefits outweigh disadvantages.
ie no lockups and it needs to have 100mhz BW.

damn, by buying it i payed for 100mhz scope!  :-DD
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on November 29, 2014, 08:45:38 am
So the "fix" worked for some, did not work for others and made it worse for the rest of people.

Seems the possible hardware issue may not be off the table yet. I have my guess why this fix did not work but I need MarkL to please do couple tests for me next week when he returns from holidays.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 29, 2014, 01:20:27 pm
So the "fix" worked for some, did not work for others and made it worse for the rest of people.

Seems the possible hardware issue may not be off the table yet. I have my guess why this fix did not work but I need MarkL to please do couple tests for me next week when he returns from holidays.

Actually I think it worked for most with a flawed keyboard.  I think two did not fix or moved the 5us jitter issue.  I did not even try it as they have not posted the current working firmware for restoring back.  I make it a habit of not ever updating anything unless it is possible to go back or guaranteed to be a positive upgrade.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on November 29, 2014, 08:24:21 pm
So the "fix" worked for some, did not work for others and made it worse for the rest of people.

Seems the possible hardware issue may not be off the table yet. I have my guess why this fix did not work but I need MarkL to please do couple tests for me next week when he returns from holidays.

Actually I think it worked for most with a flawed keyboard.  I think two did not fix or moved the 5us jitter issue.  I did not even try it as they have not posted the current working firmware for restoring back.  I make it a habit of not ever updating anything unless it is possible to go back or guaranteed to be a positive upgrade.

In my case the beta firmware made the "5us" jitter much worse. Oh, and the keyboard lockup as well.
right now, the DSO is unusable thanks to the increased jitter.
Additionally the counter function is now in error, showing something like "19.7 MHz" for a 20 MHz signal.
The function gen is good and accurate to 4 figures, my rigol DS2072 shows it is 20.00MHz but the DS1054Z
now has large error in the counter.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 29, 2014, 08:41:01 pm
right now, the DSO is unusable thanks to the increased jitter.
You can just downgrade to FW v.04.01.02.00 - available here (http://www.gotroot.ca/rigol/).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 29, 2014, 09:12:32 pm
right now, the DSO is unusable thanks to the increased jitter.
You can just downgrade to FW v.04.01.02.00 - available here (http://www.gotroot.ca/rigol/).

Has anyone tried downgrading?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on November 29, 2014, 09:23:59 pm
Has anyone tried downgrading?

Do you mean specifically from this beta version - or the thousands of times people have been up and downgrading on the Rigol UltraVision scopes in general?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: jkrichards on November 29, 2014, 09:31:00 pm
Has anyone tried downgrading?

Do you mean specifically from this beta version - or the thousands of times people have been up and downgrading on the Rigol UltraVision scopes in general?
This beta.... 
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on November 29, 2014, 10:56:16 pm
Hi All -

I just got my scope (DS2072) back from Rigol and it has a new firmware: 00.03.02.SP3. I see posts here about a beta firmware for the 1xxx series scopes, but not the 2xxx series. So I am not sure if this firmware is a beta version or not, but it does seem to have addressed the AC triggering jitter.

The attached screenshot shows a 2V P-P 25MHz square wave from my function generator. The scope is set up with AC trigger coupling (but DC channel coupling) with the trigger level set to 0V. No jitter.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on November 29, 2014, 11:41:49 pm
I just got my scope (DS2072) back from Rigol and it has a new firmware: 00.03.02.SP3
Well that sure looks like 2 bugs are fixed on a DS2000
you just Beta Tested for Rigol!   :-+
Are there any problems with Buttons?, Startup??

Can you look at the full FW version number (F7-F6-F7-Util) , format  '00.03.??.??.??'

Pix of my DS2072 today

Well, you've seen my other thread, so you know I've been doing a lot of testing for them lately :)

Software version: 00.03.02.03.00
Hardware version: 1.0.2.0.2
FPGA Version:
  SPU: 04.01.02
  WPU: 01.01.03
  CCU: 12.29.00
  MCU: 00.05
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on November 30, 2014, 12:13:48 am
Full FW version number is: 00.03.02.03.00
HW version: 1.0.2.0.2
I'm Envious,  why did you get the Beta Verson first.    ;D

I guess I am just lucky. No start-up issues or keyboard lock-ups either. I suspect they had some "work in progress" on the 1xxx series firmware, and so the people who got the jitter fix also got a bunch of untested or partially tested changes along with it.

In any event, it's good news for all of us that the problem is fixable via firmware. I am sure an official release can't be far away.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: JDubU on November 30, 2014, 12:25:25 am
Well, you've seen my other thread, so you know I've been doing a lot of testing for them lately :)

Software version: 00.03.02.03.00
Hardware version: 1.0.2.0.2
FPGA Version:
  SPU: 04.01.02
  WPU: 01.01.03
  CCU: 12.29.00
  MCU: 00.05

Did the new firmware fix the jitter that occurs on the trigger output connector as well?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on November 30, 2014, 12:31:52 am
right now, the DSO is unusable thanks to the increased jitter.
You can just downgrade to FW v.04.01.02.00 - available here (http://www.gotroot.ca/rigol/).

Has anyone tried downgrading?

I just tried now. Using the same thumb drive that successfully updated from OEM firmware (..SP3) to beta
I placed the v.04.01.02.00 firmware, renamed to DS1000ZUpdate.GEL in the thumb drive.
It is recognised as  an older version and offers to load it.
AND IT FAILS with a message "Update was failured!"
Here's hoping I have not bricked it.
By the way, is there a bootloader in the DS1054Z similar to the DS2072?

So I replaced the v.04.01.02.00 file with the beta, the one and only firmware that is available
for the DS1054Z that seems to load and the message is "Congratulations!" etc. time to reboot so enjoy the results.
First reboot, keypad and knobs locked.
Next boot, it responds as normal.
firmware v.00.04.SP3.

Let's see if the jitter remains...what do you all think?
The counter shows 19.7145 MHz from my 20.00 MHz fun gen output.
Not looking good, and yes the nearly 40 us jitter at 5us delay is still there.
At 15 us it's 75us of jitter.
I'd take a picture of this but it's too depressing to look at.
But the AC coupled trigger jitter is gone.



 

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on November 30, 2014, 12:32:59 am
Well, you've seen my other thread, so you know I've been doing a lot of testing for them lately :)

Software version: 00.03.02.03.00
Hardware version: 1.0.2.0.2
FPGA Version:
  SPU: 04.01.02
  WPU: 01.01.03
  CCU: 12.29.00
  MCU: 00.05

Did the new firmware fix the jitter that occurs on the trigger output connector as well?

Can you point me at a post that describes how to check that? I have to run an errand, but I will check for your reply when i get back and can do additional tests as appropriate.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on November 30, 2014, 02:04:32 am
Did the new firmware fix the jitter that occurs on the trigger output connector as well?
@ motocoder
 In order to check Trigger out jitter; use the 25Mhz Square wave on Chan 1 , with DC triggering
 Then just connect trigger output on back to Channel 2
MOVING TRIGGER POINT TO THE left about 230 nSEC

If you can , also Check the Trigger output , when in the AC coupled Triggering
Thank you very much for testing Motocoder

My Trigger output Jitter pix
ps fast screen capture & postings with Marmad's RUU utility

Screen shots attached. Also notable: the scope locked up while I was scrolling the display to make the trigger visible.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 01, 2014, 02:41:48 am
Thanks MarkL. I can actually see in the board level photos the two loop filter resistors marked 55B and 93A, a search on smt resistor marking resulted in 3.65K and 909 Ohm. And two out of the three capacitors could probably be measured by simply measuring the capacitance from pins CP and Tune to ground. So just one unknown will be left if do not want to disassemble the scope.

I loaded the beta software and it worked for me, although I understand it didn't work for everyone.  Before I loaded it, I captured what Rigol puts into the AD4360-7 registers in the required 3 transactions (in hex):

00 03 E9
40 31 E8
02 71 02

As a quick sanity check this loads R with 250, and 25MHz / 250 = 100kHz.  This is the divisor I was expecting.

The beta loads the following into the registers:

02 00 29
40 31 2C
00 19 02

I haven't decoded it.  From what others are experiencing, it sounds like there's still some instability.  The beta also has some fairly prominent spurs in my 1GHz output, captured on the SA below, as well as some residual modulation or perhaps phase noise.

I accessed the bottom of the board and measured the components in the loop filter and I will post them in a few minutes after I draw a small diagram.  You are right on the values you read.

For kicks before I loaded the beta, I also looked at the 1GHz output with FM demod.  Unsurprisingly, it's a well defined sawtooth.  FM demod once the beta was loaded was very flat.

EDIT: Not that it matters in this situation, but I should probably point out that the FM demod screen shot below is an aliased version of the actual waveform.  The envelope is visually the same, but the frequency is nowhere near the actual 100kHz if you look at the settings.  It's not the first time aliasing has gotten me, and probably not the last either.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 01, 2014, 03:07:34 am
Ok, Bud, here's Rigol's loop filter.  These components were measured at 100kHz on a B&K 886 LCR meter.  The measurements on the capacitors were isolated by shorting the interfering capacitors to ground.  The meter took care of the remaining parallel resistance (R1) in its measurement model, so I think these values are pretty close.  Let me know what you come up with in your modeling.

I haven't put the scope back together yet.  If you need a further test or if you suspect an issue in these component values I can probably throw together a measured Bode phase plot from CP to VTUNE.

It's too bad the beta worked for me.  There's not much for me to troubleshoot.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 01, 2014, 04:33:31 am
Thanks MarkL

Let me play with the numbers.

However it did not fix it for you, you still getting garbage out of the PLL. Less garbage but still garbage. I think the PLL is unstable, that would explain why some people think it fixed it, some not. For those who think it fixed it they may have the problem again with variation in temperature or aging.

Can you measure the 25MHz oscillator f ?

Thks!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 01, 2014, 04:40:12 am
This is the type of plot what you should be getting at a smaller frequency span

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 01, 2014, 09:15:32 am
Ok, Bud, here's Rigol's loop filter.  These components were measured at 100kHz on a B&K 886 LCR meter. 

OK, even before you measured the caps I suspected the PLL loop design was deficient, by just knowing the two resistor values. It was no matter what I did, the simulation tool could not come up with a reasonable phase margin. Now when you measured the caps and I plugged them in to the simulator it is the same thing - with this component values the phase margin value is way too low (18 degrees, whereas recommended >45) . By the book that implies potential instability of the loop.

It appears Rigol tried to make a change by increasing the PFD frequency from 100kHz to 2.5MHz (you can now see the 2.5MHz PFD leak in your last SA shots) and doing some other tweaks, it may have worked for their particular test units, but did not work for everyone in the field.

I think there may be a problem with the loop filter component values. If I configure the simulator with the same loop bandwidth but a proper phase margin, it generates totally different values for all 5 components.  I will give it another shot tomorrow, it is already 4am here.

I can also think about other deficiencies in their PLL programming (thank you for capturing the registers programming values). And the last but not least is appears to be an issue with low driving level of the clock from the PLL into the ADC. The ADC datasheet says the minimum requirement is 1.5V p-p (+7.5dBm), the PLL puts out horrible -12dBm right now based on your SA screenshot. When working properly it should be able to pump out about 0dBm, still a far cry from the minimum requirement of +7.5dBm. I have no idea how it was possible to design such a deficient circuit. Anyway, will keep digging.




Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 01, 2014, 12:46:32 pm
I can also think about other deficiencies in their PLL programming (thank you for capturing the registers programming values). And the last but not least is appears to be an issue with low driving level of the clock from the PLL into the ADC. The ADC datasheet says the minimum requirement is 1.5V p-p (+7.5dBm), the PLL puts out horrible -12dBm right now based on your SA screenshot. When working properly it should be able to pump out about 0dBm, still a far cry from the minimum requirement of +7.5dBm. I have no idea how it was possible to design such a deficient circuit. Anyway, will keep digging.

The measurement was done with a Tek P6248 1.7GHz diff probe set on divide by 10, so -11.9dBm is 1.60Vpp.  Within spec, but barely.

Sorry for the confusion.  I had already measured the Vpp into the ADC with a scope so I knew it was ok, and the frequency characteristics were more important at that point.  I should have set the offset on the analyzer so the amplitude would read true.

I will measure the crystal oscillator output when I get the Rigol re-assembled sufficiently.

Thanks for the in-depth analysis on the simulator.  I wonder if there's a single loop filter component in parallel with any of the others that would create an acceptable phase margin.  It would be an easy test to squeeze a resistor or capacitor next to one that's already there.  Unless I can get back to a released version that has the issue, maybe someone else can try it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 01, 2014, 04:26:33 pm

Can you measure the 25MHz oscillator f ?

Thks!

... And jitter, if you can

EDIT: Also Rigol in the beta has reconfigured the Lock Detect pin, it was not used before, now they configured digital lock detect on it (active high), so you can check what is going on there.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 01, 2014, 07:45:13 pm

Can you measure the 25MHz oscillator f ?

Thks!

... And jitter, if you can

EDIT: Also Rigol in the beta has reconfigured the Lock Detect pin, it was not used before, now they configured digital lock detect on it (active high), so you can check what is going on there.

The Rigol's oscillator comes in at 24.9998740MHz.  The oscillator out is a clean square wave at 3.30Vpp.

The scope I'm using (Agilent MSOX3104) does not have any delay or trigger jitter specs, so the following is in comparison to a couple of different stable crystal oscillators I have.

First, the Rigol's oscillator cycle to cycle jitter is low enough to not be observable.

Second, the best oscillator I have shows a jitter of about +/-3ns @ 100ms as compared to the Rigol's oscillator which is about +/-8ns @ 100ms.  Spot checking many delays along the way shows no cyclical jitter or any weird anomalies.

Third, the spectrum analyzer also shows the tone is extremely clean.

I think I can say with little doubt the issue is not coming from or being exacerbated by the oscillator.

However, the MUXOUT pin is always low.  Hmmm....
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 01, 2014, 08:19:48 pm
However, the MUXOUT pin is always low.  Hmmm....

And speaking of the MUXOUT pin, here's another weird thing.  In a previous post I reported the MUXOUT pin was always high, however at that time the programming for the pin was DGND, which should have forced it low.

I just double checked the SPI packet decode and it is correct.

I wonder if MUXOUT goes to the processor or somewhere else and it was accidentally being driven high.  I could have also made a mistake and probed the DVdd or LE pin which are both right next to it.

At any rate, there's no question MUXOUT is low now, but I'm bringing this whole thing up because something else could be interfering with the operation of that pin.


Does anyone know what version is in http://gotroot.ca/rigol/DS1000Z-04_01_02_00.7z (http://gotroot.ca/rigol/DS1000Z-04_01_02_00.7z) ?  Is that some hack version or is that a real release?  I see poida_pie tried it but it failed.  Has anyone succeeded?  I'd like to get back to a release before the beta.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 01, 2014, 08:31:35 pm
Quote from: MarkL
However, the MUXOUT pin is always low.  Hmmm....

No surprize here, as i said the PLL still puts out garbage, so it is still unlocked.

That is kind of thing in our scopes we want locked
 :-DD
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 01, 2014, 09:00:29 pm
Does anyone know what version is in http://gotroot.ca/rigol/DS1000Z-04_01_02_00.7z (http://gotroot.ca/rigol/DS1000Z-04_01_02_00.7z) ?  Is that some hack version or is that a real release? 
By checking a hex dump of the 2 FW files  it looks like the versions are
00.04.01.02.00
and
00.04.02.03.09
 and the nickname is the Sparrow :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 02, 2014, 01:23:37 am
Rigol has created updated firmware for the MSO1000Z and DS1000Z series of scopes in immediate response to the issues found by Dave and the EEVBlog community.

[...]

Lastly, if anyone has questions or concerns they want to discuss with us, we are always here. Contact your local Rigol office or distribution partner. Our USA number is 877-4-RIGOL-1. Every DS1000Z bought in the USA is under our 3 year warranty program and Rigol quality is important to us all over the world.

Thanks,

Chris Armstrong
Director of Product Marketing & SW Applications
Rigol Technologies
10200 SW Allen Blvd.  Suite C
Beaverton, OR 97005
office/fax: 877-4-RIGOL-1

Chris, it's time for an update from Rigol.  Quickly putting out a beta for everyone to test was appreciated, but dropping it on us like a bomb and then not participating in the ensuing discussion has not left anyone with a positive impression, to put it mildly.

There's clearly still a problem in the PLL lock.  For some people it's hidden well enough to make the scope usable, but for others it appears to destabilize the PLL even more.  This is the root cause of the jitter issue.

Plus, we now have keypad lockups and no path to re-install the released software if a user chooses to do so.

If Rigol is "always here" and "quality is important", please let us know the plan in light of the latest revelations.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on December 02, 2014, 01:28:45 am
MarkL says it very nicely.

As a minimum, easy access to the firmware version for the DS1054Z prior to the beta would be a suitable starting point.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 02, 2014, 02:13:36 am
One more thing on the MUXOUT pin...

During boot there are a few pulses that indicate it's probably working ok as a LOCK signal and nothing is interfering with it.

Yellow is MUXOUT and blue is LE, and this capture is right after the third register write to the 4360 (LE low).  There are 5 positive pulses from the PFD and then nothing further.  So there ya go.  No lock.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 02, 2014, 02:42:19 am
On my 194Mhz PLL it functions as it should. I have  a LED connected to it, which goes on when the PLL locks.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 02, 2014, 06:51:59 am

Thanks for the in-depth analysis on the simulator.  I wonder if there's a single loop filter component in parallel with any of the others that would create an acceptable phase margin.  It would be an easy test to squeeze a resistor or capacitor next to one that's already there.  Unless I can get back to a released version that has the issue, maybe someone else can try it.

OK here is what can be tried on the original (non-beta) version:

connect a 100nF capacitor across C3

This will increase phase margin from 18 to 50 degrees and dampen loop response overshoot.

Can someone with the original firmware and who has access to the inside of the scope please try and report back.

What to look for: monitor voltage on pin 24 with any low bandwidth scope, expected to change from sawtooth to flat with some high frequency noise on it. If you are fancy then use your spectrum analyzer and loose couple via may be a 10-20pF capacitor to one of the PLL output shoulders (the differential clock line that goes to the ADC). Tune to 1GHz center, 5-10MHz span, capture the screenshot.

Or if you are a poor man then just visually re-check if that fixed the 5uS jitter and may be AC trigger coupling jitter.

Unfortunately on beta that will not work, at least according to the simulator.



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 02, 2014, 07:11:26 am
Or if you are a poor man then just visually re-check if that fixed the 5uS jitter and may be AC trigger coupling jitter.

I very much doubt the two problems (5uS jitter and AC trigger coupling jitter) are related. The DS2000 suffers from the AC-coupling jitter - but not the 5us jitter.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rf-loop on December 02, 2014, 07:25:22 am
And more problems...


This Rigol individual unit what I tried to use for measure signal generator period jittter, testing  was failed in just  first steps when I try use Rigol DS1074Z   (and this individual unit do not have at all this special "5us" jitter. But have Trigger AC coupling jitter.)

This jitter what I hit is continuously over all delay settings and clearly visible after around 50us delay and its jitter p-p rise until around 100us it is maximum and then if more delay it stay around this jitter p-p level. But also if delay is more, say several ms then there is also this fast jitter but also more and more slow drifting around.


Trigger delay jitter.

I have tried measure signal generator cycle to cycle jitter. (yes not only try, also done but I find that with cheap scope measurement/test is impossible. Test turns to opposite and may ask is this device under test or test equipment itself who is tested?

Here picked up from test some tiny example. This is not fair compare due to fact these are in different price category, so it is not apples to apples.

Both oscilloscopes tested with equal signal (Rigol did not have 50 ohm input so I use external terminator for both scopes. Rigol this model can not use faster than 5ns/div, so I use same with Siglent.
(note also that pictures are same size on your monitor due to same pixel count (800x480) but Siglent have 8" and Rigol 7" TFT.)

So, signal period time 300us (no matteer, it do it with all delay settings but under 100us delay, less and less and with some 10-30us delay it go so small that difficult to see with eyes). 
Looked next rising edge fron trigger position. (300us delay)
Both scopes DC coupled, Trigger DC coupled and trig mode rising edge middle of signal vertical (0V).  Trigger mode normal.

With example  100us delay 20ppm jitter.... With this individual DS1000Z scope can not  measure even very crap class function generator signal period jitter. 

There is really something wrong and badly.

Note If you look noise that Rigol is under 1/3 BW compared to this Siglent. More BW more noise. This is Basic fundamental - normally.

(http://i181.photobucket.com/albums/x2/aghp55/SDS2000/DS1Z_QuickPrint35-300us-square-delay.png)
Rigol show original signal first so that it can imagine what is going on. Then next pictures zoomed to horizontal center (300us delay)


(http://i181.photobucket.com/albums/x2/aghp55/SDS2000/DS1Z_QuickPrint36-300us-delay-jitter.png)
Lot of jitter. Now if you do not have other scope etc ypu may think that signal generator have this over 2ns jitter over one period.  This is cheap and totally  unusable for this work.


Lets take other tool...   

(http://i181.photobucket.com/albums/x2/aghp55/SDS2000/SDS00016-300us-delay-jitter.png)
This is acceptable.  Siglent have good quality true digital side trigger engine.


And more for some imagine about performance...  delay rised to 10ms.
(now we can also see it really slows scope waveform update rate (and trigger freq counter)  because delay force scope waiting, every turn it need wait next trig + 10ms delay. Waveform update rate drops of course. (for this I turn it to dots and long persistence so that can see last capture(s), bright dots, and then persistence (old  traces)...

(http://i181.photobucket.com/albums/x2/aghp55/SDS2000/SDS00018-10ms-delay-jitter.png)

What I can say  - least I can say: "Not bad".

But with DS1000Z characterizing DUT period jitter. Can not do at all due to  its own really terrible delay jitter.

What is this whole  jitter hassle.
 
There is trigger AC coupling totally bad jitter, there is "5us" delay jitter (but this my unit do not have it with any detactaable level), there is this other kind of trigger delay jitter...  if Rigol do not know but oscilloscopes are time domain analyze tools... time domain need be as good as possible and trigger stability is one of most important thing in oscilloscope.  Now it looks like cosmetic signal make-up  is more important than Basic oscilloscope Fundamentals. 

Do we now get individual FW patches for every individual scopes... or is it more wise to call back all bad units and change/fix HW so that all can use same FW. Rigol need think what is price for reputation.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 02, 2014, 07:34:25 am
After looking at the programming values (thanks MarkL) and checking against the datasheets and common sense, I think this is what may have happened: the PLL loop filter was designed using a different chip, and later the design was used for ADF4360-7.

What makes me think so is one of the programmed parameters called Core Power Level was set to the value of 15mA in both original and beta firmware. The issue with this is per ADF4360-7 datasheet it should be 5mA. I found several references on ADI web site where they say the recommended value should be used because all of the datasheet parameters were characterized using the recommended value. They also say that the simulator will be incorrect if Core Power Level is set to any other value. So why Rigol used 15mA instead of 5mA.

ADF4360-7 is a 0.75 to 1.8GHz chip which is adequate for the 1000 series scopes. I checked other ADF4360 series ICs and sure enough ADF4360-2 which is a 2GHz chip is specified for 15mA Core Power Level. That chip may have been used in 2GSa scopes. So this may be a coincidence but appears the loop filter designed for ADF4360-2 was used for ADF4360-7. Also the 15mA setting was probably transferred over to 4360-7, too. That may have resulted in a poor PLL loop response.

That is what I think, not necessarily what in reality may have happened. But it makes sense. I plugged in the loop filter component values that MarkL measured to a ADF4360-2 simulation and it worked fairly well, phase margin was 40 degrees vs 18 degrees on ADF4360-7, and loop response was smooth with little overshoot.



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 02, 2014, 07:37:24 am
I very much doubt the two problems (5uS jitter and AC trigger coupling jitter) are related. The DS2000 suffers from the AC-coupling jitter - but not the 5us jitter.

Well no one measured clock on DS2000 yet - it may also have problems, albeit not that pronounced.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 02, 2014, 07:44:39 am
I think what has to be done first is the ADC clock (ADF4360-7 PLL)  fixed. There may be cascading problems because of the garbage clock - if you look at the downstream Hittite ADC datasheet, there is another PLL in it that supposed to lock to the ADC clock, and then output of that internal PLL goes out and may be used by the downstream FPGA. Garbage in-garbage out. I think we should focus on the 4360 PLL before going any further.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 02, 2014, 08:01:33 am
Here is information for Rigol

- see if you guys want to ask yourself why 15mA Core Power Level was used for 4360-7. In case no one knows the answer , you should change it to 5mA per the IC manufacturer recommendation and retest/redesign/resimulate the loop filter.

- second thing to ask yourself is what was the reason to use the lowest charge Pump Current of 0.31mA. You may want to pump it up to the full 2.5mA to improve loop stability - the simulator shows phase margin increase from 18 to 39 degrees by just making this change. This can be tried now with the original DS1000 firmware - this alone may get the PLL to lock and have a solution for the scopes in the field. Still , a new loop filter should be designed for the new scopes.

- the beta firmware appears to be a fail and should be reversed, at least its PLL part which made the problem worse. The PLL loop filter used in the scopes in the field did not seem to be designed for 2.5MHz PFD.

UPDATE:

- the R counter latch data  in beta is incorrect. You forget to set the VCO calibration Band Select bits. The VCO may be freewheeling at a wrong frequency to begin with.

beta : 02 00 29
should be: 22 00 29
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Vtech on December 02, 2014, 01:02:11 pm
I've tried to replicate results that rf-loop had but it seems that my unit doesn't have this "long delay jitter problem". It also doesn't have "5us jitter problem". Only "AC trigger coupling problem" is present.

Scope is MSO1074Z-S.
FW: 00.04.01.SP2
Board: 2.1.1

I don't see any jitter even at 10ms delay (1MHz test signal comes from HP fun. gen.). At ridiculous 1 second delay there is some 40ns jitter but I think this is acceptable since it is 0.04 ppm!!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RigolTechUSA on December 02, 2014, 10:33:07 pm
Thanks for all the help checking the beta. The engineers are reviewing those issues. I personally upgraded 7 or 8 units across the line and didn't see any of the keyboard, boot. or trigger issues some have reported, but engineers are looking at it. I'm going to take down the beta in a few minutes as I think we have enough feedback and some things to work on. As far as I can tell all of these issues are still firmware and not hardware and should be fixed by the scheduled release upcoming. Will let you know when that is ready. Folks should also be aware that if they are updating hacked units we can't guarantee how an update will shake out on your instrument. We don't do any regression or compatibility testing on units that have been hacked. Just keep in mind that that isn't a test case we consider when releasing firmware. If you have questions or concerns please drop me a line directly. chris_armstrong@rigol.com

regards,

Chris
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Howardlong on December 02, 2014, 10:50:45 pm
Regarding the keyboard issue, it is repeatable in that every time I switch the scope on after it's been off for a period of time, it will show the fault. To correct it, I simply switch if off and back on a second or two later after it had fully booted.

Board version is 6.1.1 by the way, Scope is MSO1074Z-S.

Not that this helps much, I can't ever remember using AC triggering before this to be honest though!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on December 02, 2014, 11:04:33 pm
Thanks for all the help checking the beta. The engineers are reviewing those issues. I personally upgraded 7 or 8 units across the line and didn't see any of the keyboard, boot. or trigger issues some have reported, but engineers are looking at it. I'm going to take down the beta in a few minutes as I think we have enough feedback and some things to work on. As far as I can tell all of these issues are still firmware and not hardware and should be fixed by the scheduled release upcoming. Will let you know when that is ready. Folks should also be aware that if they are updating hacked units we can't guarantee how an update will shake out on your instrument. We don't do any regression or compatibility testing on units that have been hacked. Just keep in mind that that isn't a test case we consider when releasing firmware. If you have questions or concerns please drop me a line directly. chris_armstrong@rigol.com

regards,

Chris


Well, as I noted before, my DS1054Z is essentially straight out of the box - not hacked and still has 20 hours on the trial options - and it has both keyboard problems after installing the beta.  It's also in the Seattle area so it could be with you to take a look at within a day...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 02, 2014, 11:45:46 pm
Found another error in programming of the PLL registers in beta. Has to do with setting the VCO startup frequency. I have updated my post #576 - see details there.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on December 03, 2014, 12:00:24 am
Well, as I noted before, my DS1054Z is essentially straight out of the box - not hacked and still has 20 hours on the trial options - and it has both keyboard problems after installing the beta.  It's also in the Seattle area so it could be with you to take a look at within a day...
As you are close why are you not bashing on their door ?  :box:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 03, 2014, 12:17:31 am
Here is information for Rigol

- see if you guys want to ask yourself why 15mA Core Power Level was used for 4360-7. In case no one knows the answer , you should change it to 5mA per the IC manufacturer recommendation and retest/redesign/resimulate the loop filter.

Holy sh!t, this never ends... In beta the Core Power was changed to 20mA, which may have severed the problem.

OK Let me throw in some quotes from ADI forum, may be then you guys reconsider.

'====
... changing the core power would have changed the VCO sensitivity, leading to a (possibly) more stable loop filter. But in many cases it may lead to more instability (and now the simulator data is invalid also).

...Using a non-specified VCO core power current changes the VCO vs. frequency characteristic completely

...In particular check the core power, it is critical that this be set to 5 mA

...Only the specified VCO core power current should be used for the ADF4360-x family

...all measurements in characterization, yield analysis and production test are based on 5 mA. Using a different VCO setting will indeed change the VCO characteristics, to characteristics that are largely unknown, except in a few limited cases. If changing the core power 'solved' the problem, my guess is that it simply masked it.

'====

I like the last one.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on December 03, 2014, 12:18:38 am
Well, as I noted before, my DS1054Z is essentially straight out of the box - not hacked and still has 20 hours on the trial options - and it has both keyboard problems after installing the beta.  It's also in the Seattle area so it could be with you to take a look at within a day...
As you are close why are you not bashing on their door ?  :box:


Not that close... about 200 miles.  Usually one day by UPS ground.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 03, 2014, 01:30:51 am
OK I found a spare 4360 PLL proto PCB, will order parts and build later this week.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 03, 2014, 02:30:55 am
OK I found a spare 4360 PLL proto PCB, will order parts and build later this week.

Sounds like fun!


Has anyone tried the JTAG port on the DS1054Z iMX283 yet?  If so, have you gotten far enough that it could be used to write some bytes to one of the SPI controllers?

Or, how about console or telnet access?  This thing runs Linux, right?  We could use devmem to write some SPI bytes.

It would be interesting to try some different values in the PLL registers without having to chop apart the hardware.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 03, 2014, 03:13:57 am
Not me...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RigolTechUSA on December 03, 2014, 05:53:56 pm
Rigol has created updated firmware for the MSO1000Z and DS1000Z series of scopes in immediate response to the issues found by Dave and the EEVBlog community.

[...]

Lastly, if anyone has questions or concerns they want to discuss with us, we are always here. Contact your local Rigol office or distribution partner. Our USA number is 877-4-RIGOL-1. Every DS1000Z bought in the USA is under our 3 year warranty program and Rigol quality is important to us all over the world.

Thanks,

Chris Armstrong
Director of Product Marketing & SW Applications
Rigol Technologies
10200 SW Allen Blvd.  Suite C
Beaverton, OR 97005
office/fax: 877-4-RIGOL-1

Chris, it's time for an update from Rigol.  Quickly putting out a beta for everyone to test was appreciated, but dropping it on us like a bomb and then not participating in the ensuing discussion has not left anyone with a positive impression, to put it mildly.

There's clearly still a problem in the PLL lock.  For some people it's hidden well enough to make the scope usable, but for others it appears to destabilize the PLL even more.  This is the root cause of the jitter issue.

Plus, we now have keypad lockups and no path to re-install the released software if a user chooses to do so.

If Rigol is "always here" and "quality is important", please let us know the plan in light of the latest revelations.

Mark, appreciate your comments. Trying to keep as up to date with the threads as possible over a long holiday weekend here in the States. As I posted yesterday, we have gathered that feedback and engineering is looking at it. We still expect to make a final FW release to fix this problem. While none of the units I tested here or any of the units in engineering that were alpha tested showed the keyboard or jitter issues on the beta we are continuing to improve its performance for everyone. I am borrowing an instrument showing keyboard issues from a EEVBlogger and hopefully that will help us confirm the next update. I will keep everyone posted as we get closer. Still expecting a final release that works for all of you on our original schedule.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mamalala on December 03, 2014, 06:08:08 pm
I will keep everyone posted as we get closer. Still expecting a final release that works for all of you on our original schedule.

Any chance to provide the original non-beta firmware? After all, it seems that the beta made things worse for some folks, so it would be good if they could go back to the original version, without going to the ridiculous process of each person having to individually contact Rigol to get a firmware. Which, btw., you folks should really stop. Simply provide the firmwares for easy download on your site and be done with it. It's called customer service ;)

Greetings,

Chris
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RigolTechUSA on December 03, 2014, 09:56:30 pm
I will keep everyone posted as we get closer. Still expecting a final release that works for all of you on our original schedule.

Any chance to provide the original non-beta firmware? After all, it seems that the beta made things worse for some folks, so it would be good if they could go back to the original version, without going to the ridiculous process of each person having to individually contact Rigol to get a firmware. Which, btw., you folks should really stop. Simply provide the firmwares for easy download on your site and be done with it. It's called customer service ;)

Greetings,

Chris

Hello, I am sorry that you had trouble with the beta. I double checked here, but the firmware doesn't enable downgrading. We have limited that to avoid compatibility issues with the latest hardware and earlier firmware versions. In fact, that is tied to the same reason we ask for serial numbers before we share firmware for upgrading. It allows us to verify compatibility and make sure there will not be issues. As our firmware gets more sophisticated in verifying versions we can hopefully make that more easily available. I believe released firmware should be available for anyone who will be helped by it, but should not be offered if there is no meaningful benefit to the user as there is always an inherent risk in any update procedure from power outages or memory stick issues. As I said in the beta release note we will need to wait until a new version is released to get you back to full operation. For anyone who loaded the beta and had issues, please email me your model and serial number and I will make sure you get a updated version as soon as possible directly. We don't have another version yet addressing the keyboard issues but as soon as we do I will let everyone know.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on December 03, 2014, 11:10:52 pm
Wow,   as a 25+ year coder I have to say that was pretty piss pore planing.   The firmware should have some way to ID the characteristics of the device and just not allow it to flash incompatible versions.   At the very least this should have been released as some sub version that would still allow downgrades.   As in you can only downgrade to the major version number,   4.xx.xx  and not 3.xx.xx.

Here,  please test our beta software...ohhh it doesn't work...so sorry.   Rigol should release the current version with a slight sub version change so people with messed up scopes can upgrade back to the current release version.    Distribute it privately and it won't be a big issue.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on December 03, 2014, 11:16:14 pm
Hello, I am sorry that you had trouble with the beta. I double checked here, but the firmware doesn't enable downgrading.
For a BETA  :o
This seems a terrible mistake.
Sure a warning was given to use at your own risk, but to introduce further problems and not have a way to reverse to the previous FW seems like asking for trouble.  :palm:

Quote
I believe released firmware should be available for anyone who will be helped by it, but should not be offered if there is no meaningful benefit to the user as there is always an inherent risk in any update procedure from power outages or memory stick issues.
This statement might be fine for a public release, but you are addressing the foremost electronic forum in the world....most members are not idiots.  |O

Firmware upgrade of ANY device has a risk as you have described, in reality the of lack of widespread problems indicates conflicting statistics.

There are many many comments throughout this forum re the availability of your FW to the point that some have moved away from Rigol's products.
i believe many would support a policy change in this matter.

We all realise that occasionally a new product or a FW update might not go as intended, it is up to the manufacturer to address issues in a prompt and timely manner, nothing more, nothing less.


I wish for these comments to be seen as coming from a Test Equipment owner and are in no way intended to incite a slanging match.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: miguelvp on December 03, 2014, 11:21:18 pm
Surely you can press help immediately right after power up to do a force firmware update if you have the previous version firmware on a USB stick, right?

Or is the DS1000 boot sequence different than the DS2000 series?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: alank2 on December 03, 2014, 11:25:41 pm
For a long time people have been able to flash different firmware versions, forward and backward...
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on December 03, 2014, 11:40:23 pm
Can't ID the hardware?

What about, 18:36 of Dave's teardown video?

https://www.youtube.com/watch?v=kb9P1Am9aFU&list=UU2DjFE7Xf11URZqWBigcVOQ (https://www.youtube.com/watch?v=kb9P1Am9aFU&list=UU2DjFE7Xf11URZqWBigcVOQ)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: 0xdeadbeef on December 03, 2014, 11:51:26 pm
I believe released firmware should be available for anyone who will be helped by it, but should not be offered if there is no meaningful benefit to the user as there is always an inherent risk in any update procedure from power outages or memory stick issues.
This is a terrible and inexcusable attitude that stops me from buying Rigol products (again). Indeed, I bought a used DG2021A once which had a firmware bug related to NI-VISA via serial and the support denied that there was a fix for this. Finally, I got the update from a kind soul who had the luck to reach a more competent and helpful support person.
Generally, companies who refuse public firmware upgrades and a publicly available release history should be avoided.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on December 04, 2014, 12:08:32 am
I wish for these comments to be seen as coming from a Test Equipment owner and are in no way intended to incite a slanging match.

I know it's in your signature, but just to make it clear to people, this comment also comes from a distributor of Siglent gear.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on December 04, 2014, 12:45:09 am
I wish for these comments to be seen as coming from a Test Equipment owner and are in no way intended to incite a slanging match.
I know it's in your signature, but just to make it clear to people, this comment also comes from a distributor of Siglent gear.
I think anybody that can read will see that.

Did I say anyting outrageous/offensive?

As your moderator asked me to declare my position re Siglent and I complied with his (read "your") wishes so now I can't make bonafide comments in the forum without somebody pointing the finger.  :wtf:

I now have to live with that ruling and its now plainly apparent implications.



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: aargee on December 04, 2014, 01:32:05 am
I think Rigol's response so far to the problem has been above average in comparison to a lot of other companies both in and outside of test gear.
Not everyone who reads or participates in this forum could be said to be experts, even if it is one or the foremost forum of its type. I understand the cautious nature of Rigols responses here and their roll out of beta software that may or may not fix problems and/or introduce new issues.

Personally, I try not to jump at freshly released software, especially if I'm no expert (- which I am some of the time  ;)  ). I checked to see if there was a roll back option, which there didn't appear to be, and left the beta alone.

I agree with Dave and the moderators that it is a poor look when distributors of competitive gear get on and start ranting and raving about the opposition and their perceived (or not) actions to fix problems in their gear. Whether or not you are acting from an independent standpoint in your head is beside the point when your sig says otherwise.

Rigol could have just left the forum alone but have chosen to take an active part in communicating, which on balance is commendable.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on December 04, 2014, 01:43:48 am
None of this will stop me from buying more Rigol gear unless they become hostile toward their customers over issues.    So far they are acting much more professional then most of us,  myself included.   Then again we're not in their shoes and can afford to bitch and whine.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on December 04, 2014, 02:16:58 am
Whether or not you are acting from an independent standpoint in your head is beside the point when your sig says otherwise.
Granted, gave that some thought and exactly why I added a footer.
I don't normally.

FYI any signature I use will instantly apply to ALL my existing posts so I have to live with this signature like a flag on my forehead.

Would you all be happier if my signature was "NZ Test Equipment Supplier"?
Is that sufficent disclosure?

Should all this discourage me from making valid comment/posts, in this thread or any other?
Just try and hold me back.  >:D
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 04, 2014, 03:41:19 am
None of this will stop me from buying more Rigol gear unless they become hostile toward their customers over issues.   

Well, did not they produced a nice letter saying they did a test and found no issues. It was all in user's heads, before we pointed out to the PLL problem.
Aren't we having a deja vu now, this time with them having tested the beta which was also successful as they say. It is again all in the heads of those who claims they have their scopes locking up and/or the issue not fixed.

Cant wait for MarkL to hook up his SA to the "final firmware-d" scope. I think I have earned some credibility here to say these guys have no idea what they are doing to the PLL. It was not a proper fix, it was a desperate attempt to patch the hole by any means, whatever seemed to work.


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on December 04, 2014, 03:55:11 am
Whether or not you are acting from an independent standpoint in your head is beside the point when your sig says otherwise.
Granted, gave that some thought and exactly why I added a footer.
I don't normally.

FYI any signature I use will instantly apply to ALL my existing posts so I have to live with this signature like a flag on my forehead.

Would you all be happier if my signature was "NZ Test Equipment Supplier"?
Is that sufficent disclosure?

Should all this discourage me from making valid comment/posts, in this thread or any other?
Just try and hold me back.  >:D


Personally, I think suppliers on this forum should take the moral high ground and not criticize their competitors in any way.  There are plenty others here that can and do 'do that'...

Asking for a policy change re. firmware availability was OK IMO.  Criticizing the Beta terms; not OK.  It was at the equipment owner's risk that they might not be able to get any problems fixed until the general availability of the firmware.  Fair enough.  I accepted that.  My scope isn't mission critical so I could afford the risk.  It's now on its way to Chris at Rigol for testing.  I see it as their beta program doing what it is supposed to do - find problems that do not show up in in house testing.  Kudos to Rigol for making the beta available and to those that took the risk installing it.  Respect to those that didn't install it due to not being able to revert to the previous firmware.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pickle9000 on December 04, 2014, 04:16:26 am
Whether or not you are acting from an independent standpoint in your head is beside the point when your sig says otherwise.
Granted, gave that some thought and exactly why I added a footer.
I don't normally.

FYI any signature I use will instantly apply to ALL my existing posts so I have to live with this signature like a flag on my forehead.

Would you all be happier if my signature was "NZ Test Equipment Supplier"?
Is that sufficent disclosure?

Should all this discourage me from making valid comment/posts, in this thread or any other?
Just try and hold me back.  >:D

I'd rather hear the argument against or for (Rigol or whoever),  at least then I can check it out for myself. It does not mean he's wrong (or right).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mamalala on December 04, 2014, 08:48:25 am
Hello, I am sorry that you had trouble with the beta. I double checked here, but the firmware doesn't enable downgrading. We have limited that to avoid compatibility issues with the latest hardware and earlier firmware versions. In fact, that is tied to the same reason we ask for serial numbers before we share firmware for upgrading. It allows us to verify compatibility and make sure there will not be issues. As our firmware gets more sophisticated in verifying versions we can hopefully make that more easily available.

I'm sorry, but i'm not really buying that. You had no problem to hand out a link to the beta firmware so that people can test it. Nowhere in that post did it say something like "This firmware is only suitable for units in the serial number / hardware revision range XXX to YYY, please do not apply to units outside thatt range". In the teardown videos there are resistor straps visible that set the revision of the unit. Did Rigol place them there just for fun, or can the firmware read out what they are set to? I would assume the latter, so the firmware should be able to differentiate.

If the firmware really can't make that distinction, then it is rather poorly designed when it comes to such stuff. Heck, even 50€ sat receivers can do it and tell you that some firmware file for another type, using the exact same hardware but having slight diffences in functionality, is not compatible with the unit the user wants to upload it to.

Unless Rigol is hand-soldering every device specifically for the customers, eaach one in turn being different, it is really hard to believe that you need to have that begging-for-firmware procedure in place. If the firmware needs to be specific for a few model revisions and/or serial number ranges, but the units are unable to figure it out on their own, then simply put that information out there together with those files. You know, like "here is firmware version A. This version is only for the series B units, hardware revision C and serial number range XX to YY. Do not apply to other units". Again, you had no problem providing a beta firmware to people without any such restrictions/information attached, which strongly hints at this not really being an issue. Don't treat your customers as stupid folks who can't read, have some confidence in them, please.

Greetings,

Chris

ETA: And as has been suggested already, if the beta firmware does not allow "downgrading" to the previous non-beta version, then simply provide the previous version with a changed version number (or whatever) so that the beta recognizes it as an update and will "update". You want people to help you figure out the issue, the least you can do is to help them revert back after they tried the beta, found issues and reported them.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on December 04, 2014, 09:14:02 am
Hello, I am sorry that you had trouble with the beta. I double checked here, but the firmware doesn't enable downgrading. We have limited that to avoid compatibility issues with the latest hardware and earlier firmware versions. In fact, that is tied to the same reason we ask for serial numbers before we share firmware for upgrading. It allows us to verify compatibility and make sure there will not be issues. As our firmware gets more sophisticated in verifying versions we can hopefully make that more easily available.

I'm sorry, but i'm not really buying that. You had no problem to hand out a link to the beta firmware so that people can test it. Nowhere in that post did it say something like "This firmware is only suitable for units in the serial number / hardware revision range XXX to YYY, please do not apply to units outside thatt range". In the teardown videos there are resistor straps visible that set the revision of the unit. Did Rigol place them there just for fun, or can the firmware read out what they are set to? I would assume the latter, so the firmware should be able to differentiate.

If the firmware really can't make that distinction, then it is rather poorly designed when it comes to such stuff. Heck, even 50€ sat receivers can do it and tell you that some firmware file for another type, using the exact same hardware but having slight diffences in functionality, is not compatible with the unit the user wants to upload it to.

Unless Rigol is hand-soldering every device specifically for the customers, eaach one in turn being different, it is really hard to believe that you need to have that begging-for-firmware procedure in place. If the firmware needs to be specific for a few model revisions and/or serial number ranges, but the units are unable to figure it out on their own, then simply put that information out there together with those files. You know, like "here is firmware version A. This version is only for the series B units, hardware revision C and serial number range XX to YY. Do not apply to other units". Again, you had no problem providing a beta firmware to people without any such restrictions/information attached, which strongly hints at this not really being an issue. Don't treat your customers as stupid folks who can't read, have some confidence in them, please.


I think what is going on is that Rigol are not testing downgrading firmware and are only releasing firmware that is tested to work as an upgrade from previous versions.  There is nothing to say that a downgrade wouldn't work, there is simply no incentive for them to spend time testing downgrades from a new firmware to every previous version that is in the wild.  If they haven't tested it, they aren't allowing it.  That would be my guess as to part of their motive.

I have to say that given the experience with the beta, I don't think that a list of "do"s and "don't"s as to which firmware works with which serial numbers/boards would work.  Some of us will go ahead and try it anyway...

I was once asked by a friend what the difference in the new version of a product I'd worked on was.  "Different bugs." was all I could say.  That seems to apply to many product releases these days, whether from Apple, Microsoft, Google or open source projects.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: womai on December 04, 2014, 09:32:05 am
tutech wrote:
>>Granted, gave that some thought and exactly why I added a footer.
>>I don't normally.
>>
>>FYI any signature I use will instantly apply to ALL my existing posts so I have to live with this signature like a flag on my forehead.
>>
>>Would you all be happier if my signature was "NZ Test Equipment Supplier"?
>>Is that sufficent disclosure?
>>
>>Should all this discourage me from making valid comment/posts, in this thread or any other?
>>Just try and hold me back.  >:D

I guess it is important to separate two things:

- The fact that you are distributor for a competing brand does not by itself mean your comments are biased; they may indeed be made in best faith and without any ulterior motives.

- The problem is that others can't know that, and some (or many) will assume they ARE biased because there is obvious incentive for them being biased. This probability increases exponentially the moment your statements don't express simple facts but rather opinions or suggestions. E.g. saying "the Siglent scope X has 100 MHz bandwidth, this is superior to Rigol scopy Y which only has 50 MHz" would not get anybody suspect bias (they may still think "you want to push YOUR products"). But saying "I would not buy Rigol products because their support is bad" is not as clear-cut objective and will immediately bring up the suspicion of bias.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: tautech on December 04, 2014, 09:46:55 am
I am careful not to make such statements especially in a thread about Rigol and hope that others would show similar courtesy.

And BTW FYI I have imported Rigol product for my customers when there have been no better alternatives.
And some of you might call me biased?  :-//

EDIT
Signature modified.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Orange on December 04, 2014, 10:34:46 am
Surely you can press help immediately right after power up to do a force firmware update if you have the previous version firmware on a USB stick, right?

Or is the DS1000 boot sequence different than the DS2000 series?
It use to work, the help button on a DS1000Z, however, with the latest firmware upgrade, RIGOL also distributed a new bootloader that needed to be installed first. I don't know if this was really needed, I did follow the procedure that RIGOL gave me, and it includes a new boot loader.

So now the HELP button does not longer work with booting....  :(
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 04, 2014, 10:41:22 am
Surely you can press help immediately right after power up to do a force firmware update if you have the previous version firmware on a USB stick, right?

Or is the DS1000 boot sequence different than the DS2000 series?
It use to work, the help button on a DS1000Z, however, with the latest firmware upgrade, RIGOL also distributed a new bootloader that needed to be installed first. I don't know if this was really needed, I did follow the procedure that RIGOL gave me, and it includes a new boot loader.

So now the HELP button does not longer work with booting....  :(

So now people have a much greater chance of bricking their scope.  :palm:

Which really sucks for me living in South Africa... It will probably cost as much as the scope did to ship it insured back to the US where it was bought from.

(Unless Rigol has an official distributor in South Africa that can deal with RMA's, does it?)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: mamalala on December 04, 2014, 10:54:31 am
I think what is going on is that Rigol are not testing downgrading firmware and are only releasing firmware that is tested to work as an upgrade from previous versions.  There is nothing to say that a downgrade wouldn't work, there is simply no incentive for them to spend time testing downgrades from a new firmware to every previous version that is in the wild.  If they haven't tested it, they aren't allowing it.  That would be my guess as to part of their motive.

I doubt that they have such a lousy record-keeping and versioning scheme in place that they are unable to keep track of what the changes in different hardware revisions are, and how those are reflected in the firmware. If they have different firmware revisions for different hardware revisions, then they should mark them as such, having a certain sub-version number tied to a specific hardware revision. People can always check on the scope itself what the actual hardware revision of their machine is, and then use the right firmware file for that. All that is assuming that they really have such a lousy bootloader/firmware upgrade mechanism which by itself is unable to detect what the actual hardware is.

And i strongly disagree about them having no incentive. Quite the opposite, i think they should have a very strong incentive to make sure that users can always revert to at least the previous firmware version easily. Just look at this thread. Allegedly Rigol themselves could not find any of the issues described on the machines they have at hand (which i find very suspicious, to be frank). This just means that what they ship to people is not what they have in-house. Which in turn suggest that the shipped units may have different issues even between each other. Thatt, in turn, means that any alleged "good" firmware upgrade can cause trouble. It would be in their best interrest to provide an easy way for users to go back to the previous firmware in case such a problem occurs.

Instead we now have people sending their scopes to Rigol so that they can figure out what is wrong with those units, since they claim that none of their units suffer from these issues. I would think it is safe to assume that during manufacture the units all get the same firmware pre-installed on them, and that Rigol knows what revision is put on scopes after a given serial number. It should be trivially easy for them to provide those firmwares, together with the info about what hardware revision / serial number range uses what firmware revision originally.

In fact, not doing so is just havoc waiting to happen. Imagine they provide a firmware update that will wreck a lot of the units out in the fild. Again, keep in mind that according to them the units out in the field must be different from the ones they have in-house. If such a thing would happen, the only way to undo it would be for people having to ship their units back to Rigol, who in turn have to fix them and ship them back out again. That would cause them way more work and trouble than simply maintaining a download archive for firmwares with the infos i suggested.

After all, most manufacturers manage to do exactly that. I don't see any good reason why Rigol should be special.

Greetings,

Chris
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 04, 2014, 11:22:59 am
After all, most manufacturers manage to do exactly that. I don't see any good reason why Rigol should be special.

Yes. If we lived in a world where Rigol was the only company that made/offered FW upgrades to their equipment, we might accept their arguments. But we don't.

In fact, as Chris points out, almost every other manufacturer in the world deals with this in a better fashion then Rigol. This - coupled with the general history of Chinese T&M manufacturers reticence plus the fact that Rigol is still doing chip-grinding and rebadging to try to hide part numbers - has to lead any logical person to believe that the nonsense surrounding FW availability (and the almost total lack of version notes for public perusal) - is due solely to Rigol's attempt to maintain some semblance of "control" over an area that should be completely aboveboard and transparent.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Orange on December 04, 2014, 12:18:03 pm
None of this will stop me from buying more Rigol gear unless they become hostile toward their customers over issues.   

Well, did not they produced a nice letter saying they did a test and found no issues. It was all in user's heads, before we pointed out to the PLL problem.
Aren't we having a deja vu now, this time with them having tested the beta which was also successful as they say. It is again all in the heads of those who claims they have their scopes locking up and/or the issue not fixed.

Cant wait for MarkL to hook up his SA to the "final firmware-d" scope. I think I have earned some credibility here to say these guys have no idea what they are doing to the PLL. It was not a proper fix, it was a desperate attempt to patch the hole by any means, whatever seemed to work.
The PLL problem seems easy to fix if you can avoid hardware changes. The good thing about this ADF chip is that Analog Devices backs it up with software that give you a possibility to simulate your design. Rigol could have done this easily.
Even without the simulation software this is not a impossible to do.  PLL loop-filter design is not a hit and miss game.   
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on December 05, 2014, 02:06:09 am
Hello, I am sorry that you had trouble with the beta. I double checked here, but the firmware doesn't enable downgrading. We have limited that to avoid compatibility issues with the latest hardware and earlier firmware versions. In fact, that is tied to the same reason we ask for serial numbers before we share firmware for upgrading. It allows us to verify compatibility and make sure there will not be issues. As our firmware gets more sophisticated in verifying versions we can hopefully make that more easily available.

I'm sorry, but i'm not really buying that. You had no problem to hand out a link to the beta firmware so that people can test it. Nowhere in that post did it say something like "This firmware is only suitable for units in the serial number / hardware revision range XXX to YYY, please do not apply to units outside thatt range". In the teardown videos there are resistor straps visible that set the revision of the unit. Did Rigol place them there just for fun, or can the firmware read out what they are set to? I would assume the latter, so the firmware should be able to differentiate.

If the firmware really can't make that distinction, then it is rather poorly designed when it comes to such stuff. Heck, even 50€ sat receivers can do it and tell you that some firmware file for another type, using the exact same hardware but having slight diffences in functionality, is not compatible with the unit the user wants to upload it to.

Unless Rigol is hand-soldering every device specifically for the customers, eaach one in turn being different, it is really hard to believe that you need to have that begging-for-firmware procedure in place. If the firmware needs to be specific for a few model revisions and/or serial number ranges, but the units are unable to figure it out on their own, then simply put that information out there together with those files. You know, like "here is firmware version A. This version is only for the series B units, hardware revision C and serial number range XX to YY. Do not apply to other units". Again, you had no problem providing a beta firmware to people without any such restrictions/information attached, which strongly hints at this not really being an issue. Don't treat your customers as stupid folks who can't read, have some confidence in them, please.

Greetings,

Chris

ETA: And as has been suggested already, if the beta firmware does not allow "downgrading" to the previous non-beta version, then simply provide the previous version with a changed version number (or whatever) so that the beta recognizes it as an update and will "update". You want people to help you figure out the issue, the least you can do is to help them revert back after they tried the beta, found issues and reported them.

UPDATE: The non-downgrade-able firmware issue does not apply to the DS2072 - at least to the beta firmware they installed on my DS2072. Apologies for my previous comments that may have led some to believe otherwise.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on December 05, 2014, 03:13:00 am
It's not hard to hate the DS1054Z now. But let's give Rigol the week or so they said they need to
provide the fixed firmware.

From what I gather from Bud and MarkL, there are a range of performances of the PLL depending on the borderline
stability of the PLL filter. I suspect that most problem DS1054Z DSOs will be fixed "well enough" in the view of Rigol.
I think there is a large variation in the degree of jitter/PLL problems, stemming from variation in values of the filter components.  Should the promised new firmware not fix my 70 ns wide jitter I plan to open the DSO
and try some different capacitors (C2 mentioned in
https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375))
And if that does not fix it, then it's either ebay or chopping block with youtube video documentation.
What would I get for a DSO with 70 ns jitter? AUS $200? probably less.
Not worth spending any more time really, I blow $50 a week on beer.




Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 05, 2014, 05:28:51 am
It's not hard to hate the DS1054Z now. But let's give Rigol the week or so they said they need to
provide the fixed firmware.

From what I gather from Bud and MarkL, there are a range of performances of the PLL depending on the borderline
stability of the PLL filter. I suspect that most problem DS1054Z DSOs will be fixed "well enough" in the view of Rigol.
I think there is a large variation in the degree of jitter/PLL problems, stemming from variation in values of the filter components.  Should the promised new firmware not fix my 70 ns wide jitter I plan to open the DSO
and try some different capacitors (C2 mentioned in
https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375))
And if that does not fix it, then it's either ebay or chopping block with youtube video documentation.
What would I get for a DSO with 70 ns jitter? AUS $200? probably less.
Not worth spending any more time really, I blow $50 a week on beer.

From what I can see, me and you are the only people that have reported being worse off with the beta FW in terms of the jitter.

I am also in the southern hemisphere and love beer too. Do I smell a conspiracy?  ^-^

Did you buy yours from a local supplier or also imported it like me?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 06:46:55 am
Should the promised new firmware not fix my 70 ns wide jitter I plan to open the DSO
and try some different capacitors (C2 mentioned in
https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375))

Do not bother if you installed the beta. Trying C2 may only work for the last firmware before the beta. As to the new firmware we first need to see what else changed.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 05, 2014, 06:53:19 am
Totally agree. In my case, Chris and team "upgraded" the firmware on my scope while they had it at their facility to use in investigating a network bug. So I had no choice in the matter. My only plan for this scope is to sell it. First that was delayed waiting for Chris and Steve to return it. Now that is delayed waiting for a firmware that doesn't randomly lock up the scope (WORSE than the situation before I sent it in for "repair").
Are you saying you can't simply downgrade the firmware via the bootloader method on the DS2000? Afaik, this would be a first for the DS2000 series.

I don't really know about the bootloader history/availability on the DS1000Z series (there is no reference to it that I can find), but if what you're saying is true, it negates the Rigol published and long-circulated document, "DS2000 DS4000 DS6000 Firmware Upgrade Procedure". (http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-01a8/0/-/-/-/-/file.pdf)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 07:39:04 am
OK , decided to have some fun with the previously posted photo of DS2000 and DS1000 PLL, on which the PLL chip on DS2000 was shaved to remove marking - photo 1 below. It was not hard to copy the needed part of the PLL image from the DS1000 board pic and superimpose on the DS2000 shaved chip in Photoshop. Some casual opacity and brightness adjustment on the inserted clip and here ya go, you can see the markings aligned nicely in picture 2, a rotated close-up picture 3 is provided for your convenience.

 :-DD

So here you have a convincing evidence the same 4360-7 chip was used in DS2000, and a small problem with that is the chip is rated for 1.85GHz max, whereas DS2000 is a 2GSa scope. What is that, bean counting trying to save by using the same chip or what. Mind boggling. Having a feeling we are about to open a fresh can of worms on DS2000. Let me throw one in right away - chances are the PLL in DS2000 suffers the exact same issue as on DS1000, i.e the PLL is not in locked state. If someone has access to DS2000 inners please check PLL pin 24 with a scope and post a screenshot.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 05, 2014, 09:42:55 am
Bud, i've got DS2072 here which i wouldn't mind opening. The only issue is -- it's the only oscilloscope here atm.  And afraid i can't probe oscilloscope by itself, can i?

Not really familiar with PLL, but if it's expected to be a constant high level guess probing with dmm would work?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Orange on December 05, 2014, 10:53:13 am
Bud, i've got DS2072 here which i wouldn't mind opening. The only issue is -- it's the only oscilloscope here atm.  And afraid i can't probe oscilloscope by itself, can i?

Not really familiar with PLL, but if it's expected to be a constant high level guess probing with dmm would work?
I would not bother opening a sealed DS2072, there is no jitter problem on a DS2000 series scope. You will probably also loose your guarantee.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: poida_pie on December 05, 2014, 12:02:34 pm

From what I can see, me and you are the only people that have reported being worse off with the beta FW in terms of the jitter.

I am also in the southern hemisphere and love beer too. Do I smell a conspiracy?  ^-^

Did you buy yours from a local supplier or also imported it like me?

Only yours and mine are worse after beta? Odds are firming for a DSO destruction on the chopping block.
I bought it from a local Rigol agent.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 05, 2014, 12:25:12 pm

From what I can see, me and you are the only people that have reported being worse off with the beta FW in terms of the jitter.

I am also in the southern hemisphere and love beer too. Do I smell a conspiracy?  ^-^

Did you buy yours from a local supplier or also imported it like me?

Only yours and mine are worse after beta?

From what I can recall. There are probably quite a few that have not applied the beta after hearing about the keyboard issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 05, 2014, 12:41:18 pm
Bud, i've got DS2072 here which i wouldn't mind opening. The only issue is -- it's the only oscilloscope here atm.  And afraid i can't probe oscilloscope by itself, can i?

Not really familiar with PLL, but if it's expected to be a constant high level guess probing with dmm would work?

In this case, the probe ground is also the scope internal ground and the signal you're probing is not synchronized to the sample clock, so yes, you can probe the scope with itself.  You could also look at the pin with a DMM but you wouldn't see any small blips if it was falling out of lock for short moments.

But more importantly (unless someone has already done it) and assuming this is indeed a 4360-7, we don't know how the MUXOUT pin has been programmed.  It could be a number of things and LOCK is only one of them.  You'd have to decode the SPI bus to know, and it appears they've conveniently provided labeled probe points for it (LE, DATA, CLK).

Although not as definitive, you might also be able to examine a long-point FFT taken with the scope of a known stable source (like a crystal oscillator).  If the sample clock is unstable you should see modulation in the FFT.  I'm not familiar with how many points the various Rigol models use for it's internal FFT calculations, so I would download the long raw waveform capture and process it externally.  Obviously this doesn't involve taking the scope apart, and it might be a good starting point that would show if there's any egregious problem.  However, it's still not proof the PLL is locked.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 05, 2014, 01:38:51 pm
I would not bother opening a sealed DS2072, there is no jitter problem on a DS2000 series scope. You will probably also loose your guarantee.

Don't think it's on the warranty (i've bought it like 2.5 years ago or so), and sending it back to rigol could cost more than the scope i'm afraid.

It's likely nothing to do with the trigger jitter indeed, it's more like a curiosity of what's going on. Maybe it's something more like "no discovered jitter issue" since the arrangement is the same as in ds1000z :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 05, 2014, 01:42:46 pm
MarkL, i'll check tomorrow if i can get second scope here. If not i'll try to probe itself without blowing it up :)

As for instability in the clock, my first thought after watching the video was whether using external low-drifting clock (like rubidium standard) would do any difference to the jitter issue on ds1000z series.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Orange on December 05, 2014, 01:51:48 pm
I would not bother opening a sealed DS2072, there is no jitter problem on a DS2000 series scope. You will probably also loose your guarantee.

Don't think it's on the warranty (i've bought it like 2.5 years ago or so), and sending it back to rigol could cost more than the scope i'm afraid.

It's likely nothing to do with the trigger jitter indeed, it's more like a curiosity of what's going on. Maybe it's something more like "no discovered jitter issue" since the arrangement is the same as in ds1000z :)
Well the PLL in a DS2000 runs at 2GHz, the one in the DS1000z on 1 GHz, also we don't know the loop filter component values of the DS2000 and we don't know how the chip is programmed.
But I really doubt there is a similar problem that needs fixing on the DS2000 since is no jitter on these beauties.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 02:55:32 pm
Yes there is a common issue with DS 2000 . The AC coupling trigger jitter.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Orange on December 05, 2014, 03:12:24 pm
Yes there is a common issue with DS 2000 . The AC coupling trigger jitter.
Where are talking about the PLL jitter issue in this topic. The AC coupling jitter issue has nothing to do with PLL instability in the DS1000z. I'm not sure why you bring this up. Are you simply trolling now ?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 03:47:35 pm
Only yours and mine are worse after beta?

That is sufficient to say the beta did not correct the issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 05, 2014, 03:49:04 pm
MarkL, i'll check tomorrow if i can get second scope here. If not i'll try to probe itself without blowing it up :)

As for instability in the clock, my first thought after watching the video was whether using external low-drifting clock (like rubidium standard) would do any difference to the jitter issue on ds1000z series.
If you have the opportunity for additional equipment, I would go for a spectrum analyzer too.  Bud described a probing technique to minimize loading the output, here:

  https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg561375/#msg561375)

But at these frequencies even an insulated loop laid over one of the output capacitors would couple enough energy to examine the spectrum envelope.

Rubidium standards have PLLs in them too, so long as you know your output is stable.  I have one of the ever-so-popular FE5680A, and while long term it's very stable, it does exhibit a little more short-term jitter than a crystal oscillator.  Still fine for what we're doing here, though.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 04:21:15 pm
I have parts on order and will assemble a good clock source and can ship to anyone who is willing to test it on their scope.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 04:24:41 pm
Yes there is a common issue with DS 2000 . The AC coupling trigger jitter.
Where are talking about the PLL jitter issue in this topic. The AC coupling jitter issue has nothing to do with PLL instability in the DS1000z. I'm not sure why you bring this up. Are you simply trolling now ?
I will let people judge based on contribution who is trolling.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on December 05, 2014, 04:31:41 pm
Totally agree. In my case, Chris and team "upgraded" the firmware on my scope while they had it at their facility to use in investigating a network bug. So I had no choice in the matter. My only plan for this scope is to sell it. First that was delayed waiting for Chris and Steve to return it. Now that is delayed waiting for a firmware that doesn't randomly lock up the scope (WORSE than the situation before I sent it in for "repair").
Are you saying you can't simply downgrade the firmware via the bootloader method on the DS2000? Afaik, this would be a first for the DS2000 series.

I don't really know about the bootloader history/availability on the DS1000Z series (there is no reference to it that I can find), but if what you're saying is true, it negates the Rigol published and long-circulated document, "DS2000 DS4000 DS6000 Firmware Upgrade Procedure". (http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-01a8/0/-/-/-/-/file.pdf)

Nope, I just assumed (and I think we all know what happens when you do that) that the problem applied to any scope running a recent beta, and I was a bit fearful to try a downgrade, have it fail and render the scope useless. But I overcame my fear and tried it. It downgraded to 00.03.01.00.04 with no issues, so I'm a happy camper again.

Chris and Steve - sorry for my previous comments based on my faulty assumption.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 04:35:20 pm
Well the PLL in a DS2000 runs at 2GHz, the one in the DS1000z on 1 GHz, also we don't know the loop filter component values of the DS2000 and we don't know how the chip is programmed.
But I really doubt there is a similar problem that needs fixing on the DS2000 since is no jitter on these beauties.

We do know the resistors values in the loop filter on DS2000 are the same as on DS1000. This can be seen in the above photos and from what MarkL measured on his DS1000. Then, because of the mathematical formulas for loop filters the capacitors have to be also be the same as in DS1000. Therfore the loop filter is the same . Guess what, loop filters are designed for a specific internal detector frequency. That means good deal of programming is the same on both models.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 05, 2014, 05:01:39 pm
Just to Summarize ; I understand there are 3 jitter occurrences
                                      DS1000       DS2000
  1. DC Trigger (5us delay)          Yes           No       
  2. AC Trigger                      Yes          Yes
  3. Trigger Output                  Yes          Yes


And that the PLL affects #1



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 06:45:20 pm
Please offer a reasonable explanation why AC coupled trigger issue had not been addressed for two years and all of a sudden a fix was announced in beta when we pointed out to the problem with the PLL.

And please offer a reasonable explanation why Rigol was quick to announce DS2000 will be also updated for AC coupled trigger issue.

Here is my reasonable explanation: AC coupled  trigger is somehow derived from the clock. Garbage clock, garbage AC trigger. The 5uS issue in DS2000 may have been masked because the clock is 2GHz. What is the exact dependency I certainly not have enough information to say.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 05, 2014, 06:47:55 pm
Only yours and mine are worse after beta?

That is sufficient to say the beta did not correct the issue.

And by the way, from MarkL's Spectrum Analyzer data it did not correct for him either, just made it less pronounced. So whoever thinks it fixed the issue for them are sitting on a time bomb ticking to explode.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 05, 2014, 06:50:49 pm
Please offer a reasonable explanation why AC coupled trigger issue had not been addressed for two years and all of a sudden a fix was announced in beta when we pointed out to the problem with the PLL.

And please offer a reasonable explanation why Rigol was quick to announce DS2000 will be also updated for AC coupled trigger issue.

Well, I don't know if the problems are related, but the answer to these questions is blatantly obvious. Dave made a video decrying the bug(s) which has garnered a bunch of attention - period. To cite this as evidence of anything else is silly.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 05, 2014, 09:31:30 pm
Although not as definitive, you might also be able to examine a long-point FFT taken with the scope of a known stable source (like a crystal oscillator).  If the sample clock is unstable you should see modulation in the FFT.  I'm not familiar with how many points the various Rigol models use for it's internal FFT calculations, so I would download the long raw waveform capture and process it externally.  Obviously this doesn't involve taking the scope apart, and it might be a good starting point that would show if there's any egregious problem.  However, it's still not proof the PLL is locked.
Thought I'd provide an example of what you might see in a raw FFT from the DS1054Z running beta.  If you did just the jitter test, as I first did, you might think it fixed.  But look at the FFT of a 10MHz source.  Note the similarity to the spectrum analyzer screen shot beta_main_carrier_640x480.jpg previously posted:

  https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg560788/#msg560788 (https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/msg560788/#msg560788)

You can see the same modulation in the main carrier.  Plus a mess of other spurs, but it's not clear at this point where those are coming from.

For comparison, also included is the same source with a raw FFT from an Agilent.

The Rigol is a 1.1Mpt capture and the Agilent is 4MPts.  1.1MPt was all I could get out of the Rigol without additional contortions.  Its SCPI Ethernet implementation is quite buggy.

The source does have those spurs at +/- 2MHz @ -70dBc.  And ignore the absolute amplitude on the Rigol capture.  It's supposed to be dBV, but I think the channel units are not converting right when grabbing the raw data.

EDIT:  Oh, and Rigol was 1GS/s, Agilent 5GS/s.  Each had 1 channel running.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 05, 2014, 09:58:36 pm
Please offer a reasonable explanation why AC coupled trigger issue had not been addressed
Well, I don't know if the problems are related, but the answer to these questions is blatantly obvious. Dave made a video decrying the bug(s) which has garnered a bunch of attention - period.
I agree , Dave Jones has a bit of influence. 
Is it a case of 'The squeaky wheel gets the Oil' ?
There are lots of complaints
Also when a bug propagates on to the next model,  shows lack of ????

When Dave Jones shows my E-mail to Rigol from July 2013 in #685 could shame Rigol,
( more like manage sales/profits)

As Marman has asked once , will Rigol make this an important FW release in order to include the block of Hacks and downgrades?

Looking back at the FW of the DS1052,  Rigol must have learnt something.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: (In)Sanity on December 05, 2014, 10:32:18 pm
Quote
Is it a case of 'The squeaky wheel gets the Oil' ?

The squeaky wheel doesn't get the oil in today's society,  it gets replaced by an inexpensive Chinese equivalent.

Jeff
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 06, 2014, 07:53:27 am
OK Digikey was quick as usual and a ADF4360-7 based 1 GHz clock board now is up and running. I configured 2.5MHz PFD (same as beta) and calculated my own loop filter. Attached are side by side screenshots what MarkL captured on his beta (left) and my PLL clock (right), scaled to a same frequency span. No comments.

Sure enough an LED connected to the PLL MUXOUT pin (which was programmed for Digital Lock Detect) turns on , indicating the PLL is locked to the reference. The voltage on the CP (loop filter) pin is DC 1.1V with a small <3mV rms noise.

If the left stuff is what Rigol will be pushing on their final update, based on the optimistic posts from Rigol NA, I wish you guys good luck with your scopes.

Those who are still concerned we can discuss next steps.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 06, 2014, 08:43:15 am
MarkL, i'll check tomorrow if i can get second scope here. If not i'll try to probe itself without blowing it up :)

As for instability in the clock, my first thought after watching the video was whether using external low-drifting clock (like rubidium standard) would do any difference to the jitter issue on ds1000z series.

Thank you Sergey, will wait for your test results.
As to external clock, rubidium standards put out 10-15MHz , so you cannot just use one for the scope, you may still need to use a PLL and reference it from that low frequency standard. For the 1Ghz clock i just built i used a low jitter integrated TCXO. Sufficient for the purpose.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 06, 2014, 12:45:53 pm
Thank you Sergey, will wait for your test results.
As to external clock, rubidium standards put out 10-15MHz , so you cannot just use one for the scope, you may still need to use a PLL and reference it from that low frequency standard. For the 1Ghz clock i just built i used a low jitter integrated TCXO. Sufficient for the purpose.

So, bad news are -- i couldn't have get access to an extra scope, so used self-probing. Also i don't have access to the spectrum analyzer, can only do FFT in the scope itself. Don't think it's so much accurate and useful? Good news is that my scope is still operational :)

What i did is soldered a small piece of wire to the cap which seems to be connected to pin 24 of the PLL. Unless i'm wrong it's bottom pin on the left side of the chip. Attached the picture so one could doublecheck i got the pinout correct (extra eyes never hurts, you know :)

Now, not sure how to make a nice screenshot on the scope so i made photos with my creepy camera (so excuse me for the crudity of the model) and also saved traces with the scope. Never used them before and couldn't find an application in few minutes.

Anyway, hope it gives some bit of information.

P.S. Scope is still open so can do some additional non-destructive tests.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 06, 2014, 05:47:17 pm
Thank you Sergey. Can you turn on 20MHz bandwidht limit on the channel input and see how much noise goes away.
The screenshot shows 2.35 v DC which is close to 2.5v limit in the datasheet but still within the spec. Seems to have pretty noticeable ~100kHz spikes which most likely come from PFD. I will measure my PLL using same 500mV/ vertical gain to see how noise track compared with yours.

Also can you try turning AC trigger coupling on and see if that causes any changes to the voltage on CP pin.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 06, 2014, 06:43:09 pm
I made a mistake previous time -- silly me didn't connect the probe ground assuming it's not needed since the ground is all the same. I was wrong :(

With probe ground  properly connected spikes amplitude goes down to 180-200mV. AC trigger doesn't seems to make anything noticeable (apart form trickier trigger coz of jitter, used single shot of a long timeframe for comparison and didn't see huge difference).

With 20MHz bandwidth limit the noise is down to about 50-60mV.

EDIT: Just clarify: there's no difference with both noise and DC level of the CP pin between DC and AC trigger coupling.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 06, 2014, 08:29:59 pm
Thanks Sergey. Even with the 20MHz bandwidth limit it is still 12dB or more worse noise than my homebrewed PLL. Would be interesting to look at the spectral chart.

MarkL, what did you use to download large waveform samples? I tried a software praised in another thread but i only get 1k samples or something, though i set a large memory buffer on the scope. Is a SCPI command for it?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 12:15:02 am
MarkL, what did you use to download large waveform samples? I tried a software praised in another thread but i only get 1k samples or something, though i set a large memory buffer on the scope. Is a SCPI command for it?

It's a program I wrote in Linux octave with its optional sockets package.  It's still incomplete and was originally written for the Agilent scope and works fine for it, but now it's a total structural mess to accommodate quirks in the Rigol.  And it doesn't work consistently on the Rigol.  I would try the other package you have first since that no doubt can handle the Rigol weirdness better.

I was stuck at 1200 points also.  Here are the relevant oddities I discovered for a large download:

- You can't buffer multiple commands into the SCPI port.  One command at a time and wait for the response (if any).

- You can only change the memory record size when the capture is running.

- If you set the scope to anything larger than 1.2MPts (1200000) it sometimes returns a 0 point result.

- You have to set the ending waveform point, otherwise it defaults to 1200 points returned.

- You can't set the ending point to 1200000, otherwise you get 0 points.  I used 1100000 (:WAVeform:STOP 1100000).

- Even if you do capture more than 1.2MPt, I couldn't get it to return much more than 1100000 points anyway (when it didn't return 0).  I think setting the start and stopping points would eventually allow retrieval of the entire memory but I didn't bother doing it.  1.1MPts was enough to show what I wanted.

So, the crucial things to do are:

  :run
  :ACQuire:MDEPth 1200000
  :stop
  :WAVeform:STOP 1100000

Waveform is captured at this point.  I used the following to do the raw download:

  :WAVeform:mode raw
  :WAVeform:PREamble?
  :waveform:data?

Once set up, maybe your package can do the download since the preamble is correct at this point.

You might have better luck saving the waveform to the USB drive, but I didn't try it.  If this still doesn't do it for you, I can try and clean up the octave code a little.


If anyone is going to start diving deep into SCPI bugs, please start a new thread or perhaps take it to the Bugs/Anomalies thread.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 07, 2014, 08:36:10 am
Thanks Sergey. Even with the 20MHz bandwidth limit it is still 12dB or more worse noise than my homebrewed PLL. Would be interesting to look at the spectral chart.

The way i'm measuring it is not actually totally nice -- there's a piece of wire from the cap to the probe, plus i'm using the ground lead (not the springy needle). That gives some additional noise. Not sure it could be 12dB tho.

I don't have anything better to get a spectral chart than built-in FFT function, which i've attached. There are two images -- first one is with DC channel coupling, second one is with AC channel coupling. Not sure it's expected to be such a difference in FFT?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 07, 2014, 03:50:44 pm
Tanks Sergey. Of course should not be difference in FFT if you measure the same signal. AC coupled trigger supposed to be for triggering and not supposed to change the signal digitization in the measurement path. So something is smelling fishy.
The FFT charts have a small  frequency span though, can you do it over a couple MHz (place center of the chart to 1MHz)

EDIT: It can also be seen the AC coupled track is worse in noise going as much as 20dB worse by the right side of the chart.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 07, 2014, 04:04:28 pm
You might have better luck saving the waveform to the USB drive, but I didn't try it.  If this still doesn't do it for you, I can try and clean up the octave code a little.


Thanks MarkL, please do not bother, sounds like a learning problem for which I do not have time, but I will try saving on the USB drive.

Do you want to try the good clock source that I build - I can send it to you (you can PM me your email). You will need SMT soldering equipment though to remove the existing coupling capacitors on the scope's board to inject the new clock.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 07, 2014, 04:32:02 pm
Tanks Sergey. Of course should not be difference in FFT if you measure the same signal. AC coupled trigger supposed to be for triggering and not supposed to change the signal digitization in the measurement path. So something is smelling fishy.
The FFT charts have a small  frequency span though, can you do it over a couple MHz (place center of the chart to 1MHz)

EDIT: It can also be seen the AC coupled track is worse in noise going as much as 20dB worse by the right side of the chart.

I's not AC couple trigger, it's AC coupled signal. AC coupled trigger doesn't make any difference to the signal. AC coupled signal allows me to see the noise in a smaller scale, but has some strange effect on the FFT. Probably FFT tries to decompose the DC offset, leading to loads of harmonics.

Also, i'm not really familiar with the FFT function and seems it only depends on the timebase of the signal itself. Meaning, reducing the timebase moves the center point of the spectrum and affects on the horizontal scale as well. Doesn't seem it's possible to move the spectrum window separately from the signal itself. Or i'm missing something.

Anyway, tried my best to get some wider span recording with 1.75MHz as the center. Hope it makes sense :)

P.S. Can easily do some extra measurements if there'll be some instructions about how exactly to use FFT of the scope.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 04:33:34 pm
Thanks Sergey. Even with the 20MHz bandwidth limit it is still 12dB or more worse noise than my homebrewed PLL. Would be interesting to look at the spectral chart.

The way i'm measuring it is not actually totally nice -- there's a piece of wire from the cap to the probe, plus i'm using the ground lead (not the springy needle). That gives some additional noise. Not sure it could be 12dB tho.

I don't have anything better to get a spectral chart than built-in FFT function, which i've attached. There are two images -- first one is with DC channel coupling, second one is with AC channel coupling. Not sure it's expected to be such a difference in FFT?

You should use a different window, like Hanning, to do this measurement.  You're using rectangle and it's causing a lot of leakage across the frequency domain.  You would typically use rectangle for impulse waveforms.

Also the triggering should not affect the FFT.  As a matter of fact, as long as you have a signal, it does not even need to be triggered for FFT (as long as averaging is not on).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 07, 2014, 04:41:07 pm
You should use a different window, like Hanning, to do this measurement.  You're using rectangle and it's causing a lot of leakage across the frequency domain.  You would typically use rectangle for impulse waveforms.

Also the triggering should not affect the FFT.  As a matter of fact, as long as you have a signal, it does not even need to be triggered for FFT (as long as averaging is not on).

Good to know :)

Here are some FFTs with Hamming window.

And just to clarify again: it's not trigger which causes the difference, it's coupling of signal itself which gives issues. But as said, it could be just DC offset being decomposed into harminics. Kind of makes sense.

EDIT: Would it make sense to use some averaging? Seems there's some uncorrelated noise which almost goes away with averaging of 8-16.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 04:42:57 pm
Also, i'm not really familiar with the FFT function and seems it only depends on the timebase of the signal itself. Meaning, reducing the timebase moves the center point of the spectrum and affects on the horizontal scale as well. Doesn't seem it's possible to move the spectrum window separately from the signal itself. Or i'm missing something.

Anyway, tried my best to get some wider span recording with 1.75MHz as the center. Hope it makes sense :)

P.S. Can easily do some extra measurements if there'll be some instructions about how exactly to use FFT of the scope.

I don't have this scope, but in reading the manual I think the center and span of the FFT can be adjusted by selecting the MATH channel and then adjusting the horizontal position and horizontal scale.  My best interpretation anyway; it's poorly worded.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 07, 2014, 04:46:23 pm
I don't have this scope, but in reading the manual I think the center and span of the FFT can be adjusted by selecting the MATH channel and then adjusting the horizontal position and horizontal scale.  My best interpretation anyway; it's poorly worded.

Yes, to some degree. Can go from like 100KHz to 800KHz for the given signal time base. It's really doggy thing in my opinion. Well, what could we expect from a builtin software FFT? :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 04:49:44 pm
You should use a different window, like Hanning, to do this measurement.  You're using rectangle and it's causing a lot of leakage across the frequency domain.  You would typically use rectangle for impulse waveforms.

Also the triggering should not affect the FFT.  As a matter of fact, as long as you have a signal, it does not even need to be triggered for FFT (as long as averaging is not on).

Good to know :)

Here are some FFTs with Hamming window.

And just to clarify again: it's not trigger which causes the difference, it's coupling of signal itself which gives issues. But as said, it could be just DC offset being decomposed into harminics. Kind of makes sense.

EDIT: Would it make sense to use some averaging? Seems there's some uncorrelated noise which almost goes away with averaging of 8-16.
Looks a little better, but I think you need some better resolution for the FFT.  You can try selecting Chan1 (not Math) and reducing the sweep speed to squash the waveform horizontally.  It will probably end up resetting some of the FFT display settings, but again I'm not sure how Rigol behaves.

With a lower sweep speed you might be able to resolve some of those hills into sharper peaks, but this is also very dependent on how many points Rigol uses for FFT, which again I don't know and I don't see on a spec sheet.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 05:01:24 pm
You might have better luck saving the waveform to the USB drive, but I didn't try it.  If this still doesn't do it for you, I can try and clean up the octave code a little.


Thanks MarkL, please do not bother, sounds like a learning problem for which I do not have time, but I will try saving on the USB drive.

Do you want to try the good clock source that I build - I can send it to you (you can PM me your email). You will need SMT soldering equipment though to remove the existing coupling capacitors on the scope's board to inject the new clock.

Thanks for the offer, Bud.

I have the equipment to tackle anything SMT, but once I do that I can't in good conscience try to return the scope, which at the moment is where it's headed with the brain-dead beta.  The PLL doesn't quite bother me so much as the keypad locking up, and bugs galore wherever I turn.

But if I do start unsoldering components, I'll probably end up giving it away anyway.  There's someone I know who just started as an EE undergrad.

Let me give it some thought if there are no other takers.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 07, 2014, 05:11:22 pm
Looks a little better, but I think you need some better resolution for the FFT.  You can try selecting Chan1 (not Math) and reducing the sweep speed to squash the waveform horizontally.  It will probably end up resetting some of the FFT display settings, but again I'm not sure how Rigol behaves.

With a lower sweep speed you might be able to resolve some of those hills into sharper peaks, but this is also very dependent on how many points Rigol uses for FFT, which again I don't know and I don't see on a spec sheet.

That'd reduce resolution of the FFT for as long as i concerned. That's because on Rigols all the math functions are done in software, and seems it uses data from the framebuffer (think Dave covered this with better explanation in one of his video, where he showed a trap for young players where A+B didn't work correct when one of the traces wend out of the visible area of the screen).

So afraid we're quite close to what we can expect from this FFT..
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 05:12:12 pm
EDIT: Would it make sense to use some averaging? Seems there's some uncorrelated noise which almost goes away with averaging of 8-16.
Ooops I didn't address this question -

Averaging will improve the waveform display, but I have also seen it introduce some weird side affects into FFTs that are likely implementation dependent.  I usually don't use averaging for that reason.

If you turn on averaging and it does more than just lower the noise floor of the FFT, like create additional spurs, don't use it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 07, 2014, 05:15:20 pm
Averaging will improve the waveform display, but I have also seen it introduce some weird side affects into FFTs that are likely implementation dependent.  I usually don't use averaging for that reason.

If you turn on averaging and it does more than just lower the noise floor of the FFT, like create additional spurs, don't use it.

Hah, tried and indeed it's weird. So yes, don't recommend it :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 05:27:31 pm
Ok, so Bud, can you see what you were looking for (or perhaps the lack of it) in sergey's captures?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 07, 2014, 05:39:06 pm

Let me give it some thought if there are no other takers.

OK on that , MarkL.

I wonder if you have access to the ADC chip (pins 17-20) to measure its internal PLL spectrum, which is judging by limited information in the datasheet should lock to the ADC clock, which currently is bad.

http://www.hittite.com/content/documents/data_sheet/hmcad1511.pdf (http://www.hittite.com/content/documents/data_sheet/hmcad1511.pdf)

This could be the way garbage is propagated all down the stream into the scope. Who knows if it may have to do with the scope keys lock ups.

PS: may be I should stop using the garbage word, 'cause this may be offensive to real innocent garbage, out of which a lot of good things can be made. Rigol's clock is worse than that. May be I should call it the "chaos clock".

Definition from Webster dictionary:
"Chaos:  complete confusion and disorder : a state in which behavior and events are not controlled by anything"

Cant say any better.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 06:16:58 pm
I wonder if you have access to the ADC chip (pins 17-20) to measure its internal PLL spectrum, which is judging by limited information in the datasheet should lock to the ADC clock, which currently is bad.

http://www.hittite.com/content/documents/data_sheet/hmcad1511.pdf (http://www.hittite.com/content/documents/data_sheet/hmcad1511.pdf)

This could be the way garbage is propagated all down the stream into the scope. Who knows if it may have to do with the scope keys lock ups.

PS: may be I should stop using the garbage word, 'cause this may be offensive to real innocent garbage, out of which a lot of good things can be made. Rigol's clock is worse than that. May be I should call it the "chaos clock".

Definition from Webster dictionary:
"Chaos:  complete confusion and disorder : a state in which behavior and events are not controlled by anything"

Cant say any better.

That would be interesting to look at.  Great idea.

Just glancing at it under the microscope it's going to be harder to get the diff probe in there because the heatsink and the heatsink clip are in the way.  I'll see what I can do.  Probably later this evening.

The ADC PLL could be smoothing out some of the modulation in the incoming clock.  I was wondering why the close-in peaks next to the main carrier on the SA vs. the FFT of a 10MHz signal were so much lower.  We'll see.

I sincerely doubt any of the sample clock weirdness has anything to do with the keypad lockups.  The keypad is under control of the main processor and it has its own clock.

Since we all have our theories, I'll put mine forward and say that they added code to the keypad driver to look for some held-in combination when the thing is booting and they blew it.  Why else would you mess with a working keypad driver.  But who knows.  Total conjecture on my part.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 07, 2014, 06:59:17 pm
Since we all have our theories, I'll put mine forward and say that they added code to the keypad driver to look for some held-in combination when the thing is booting and they blew it.  Why else would you mess with a working keypad driver.  But who knows.  Total conjecture on my part.

The DSO is still fully-functional when it boots with the keypad locked, responding to any and all SCPI commands - even the IEEE 488.2 common command *RST - which will reset the DSO to it's factory settings (but doesn't start the keypad working). The scope is acting as if the :SYSTem:LOCKed command has been turned on, although it reports (via SCPI) that the LOCK is OFF.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 07, 2014, 11:30:29 pm
I wonder if you have access to the ADC chip (pins 17-20) to measure its internal PLL spectrum, which is judging by limited information in the datasheet should lock to the ADC clock, which currently is bad.

DWS1054Z single channel sampling at 1GS/s.  LCLK = 500MHz, FCLK = 125MHZ as expected.

It looks like the ADC PLL is faithfully following the input clock.  No surprises here.

The good thing is that it doesn't completely throw the ADC PLL into chaos.

PS - Analyzer offset now set properly for your amplitude viewing pleasure.


EDIT:  Added FCLK and LCLK in the time domain.  Scope BW = 1GHz, so maybe there's some detail we're not seeing.  But I would expect a better FCLK signal.  Maybe it's not terminated properly.  These traces were taken with a 1.7GHz differential probe.

The probe input was double checked with a clean 100MHz signal afterwards.  It is NOT the probe.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: rs20 on December 08, 2014, 12:09:00 am
...
It looks like the ADC PLL is faithfully following the input clock.  No surprises here.
...

Just curious, if we saw a PLL with 500 MHz output locked to a jittery 125 MHz input, shouldn't a 100ppm error on input frequency lead to a 100ppm error on output frequency? Yet, we're seeing a 127 kHz side-peak on 125 MHz signal (100ppm frequency error) leading to a 125 kHz side-peak on 500 MHz (25 ppm). To be fair, I don't have any decent intuition on how jitter is supposed to look on spectrum analysers, but can someone explain how the frequency scale is being translated 375 MHz rather than scaled 4x here?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on December 08, 2014, 01:52:17 am

Since we all have our theories, I'll put mine forward and say that they added code to the keypad driver to look for some held-in combination when the thing is booting and they blew it.  Why else would you mess with a working keypad driver.  But who knows.  Total conjecture on my part.


I suppose that's possible, but my money would be on an uninitialized variable in the keypad initialization code.  Leave the scope off for a while and the RAM tends to boot up in a certain state; on some scopes that state causes the hang.  Restart the scope and the RAM tends to keep the last value stored which would seem to enable the keypad.  If the source were in front of me, it would be the first place I'd look anyway.

Orin.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 08, 2014, 02:12:55 am
MarkL - thanks a bunch for the work you have done, we are fortunate to have you here with all your nice test equipment, except the Rigol scope which is itself being under test.

So we can now say the RCC (Rigol Chaos Clock) is not limited to just channel input signal sampling and is propagated to the downstream bus, causing whatever damage. By other words, until Rigol delivers the proper fix,

YOU GUYS CANNOT TRUST YOUR RIGOL SCOPE

Such a fix would be a change that will get the ADF4360-7 PLL (ADC clock source) to generate the proper 1GHz signal. I have attached a side by side screenshots again what it is now and what it has to be. Can this be done without a hardware change - I personally doubt but that is IMHO.

Here is what the ADC datasheet says in regards to clock:

...The quality of the input clock is extremely important for high-speed, high-resolution ADCs
...If the clock is generated by other circuitry, it should be re-timed with a low jitter master clock as the last operation before it is applied to the ADC clock input
.



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 08, 2014, 02:21:13 am
To be fair, I don't have any decent intuition on how jitter is supposed to look on spectrum analysers,
Jitter can be mathematically calculated from spectral data by integrating the area under the spectrum curve over a given frequency range, there is a ADI document explaining this:

http://www.analog.com/static/imported-files/tutorials/MT-008.pdf (http://www.analog.com/static/imported-files/tutorials/MT-008.pdf)

Using this technique, one can see in the last attachment I posted, by looking at the area under the curves that Rigol existing jitter on the left picture is huge compare to a proper clock source on the right one.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: motocoder on December 08, 2014, 02:42:02 am

Since we all have our theories, I'll put mine forward and say that they added code to the keypad driver to look for some held-in combination when the thing is booting and they blew it.  Why else would you mess with a working keypad driver.  But who knows.  Total conjecture on my part.


I suppose that's possible, but my money would be on an uninitialized variable in the keypad initialization code.  Leave the scope off for a while and the RAM tends to boot up in a certain state; on some scopes that state causes the hang.  Restart the scope and the RAM tends to keep the last value stored which would seem to enable the keypad.  If the source were in front of me, it would be the first place I'd look anyway.

Orin.

Just about any C compiler is going to flag that, though.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: orin on December 08, 2014, 03:31:40 am

Since we all have our theories, I'll put mine forward and say that they added code to the keypad driver to look for some held-in combination when the thing is booting and they blew it.  Why else would you mess with a working keypad driver.  But who knows.  Total conjecture on my part.


I suppose that's possible, but my money would be on an uninitialized variable in the keypad initialization code.  Leave the scope off for a while and the RAM tends to boot up in a certain state; on some scopes that state causes the hang.  Restart the scope and the RAM tends to keep the last value stored which would seem to enable the keypad.  If the source were in front of me, it would be the first place I'd look anyway.

Orin.

Just about any C compiler is going to flag that, though.


Unfortunately, the warning often gets turned off due to false positives.  What to do?  Add unnecessary initializations or turn the warning off/reduce the warning level?  Or leave the warning on and initialize the variable in debug builds only...?  I've seen it all and it's still the first place I'd look.

Orin.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 08, 2014, 06:47:25 am
Ok, so Bud, can you see what you were looking for (or perhaps the lack of it) in sergey's captures?

Yes, thanks to Sergey for his time spent on testing. While the PLL in it did not seem to have a pronounced problem as the DS1000 did and seems to be locked, the voltage on the CP pin is much noisier than on my home brewed PLL, which may indicate suboptimal configuration for the PLL in DS2000. I would not be surprised knowing how crappy the DS1000 PLL programming was, that Rigol did not obey ADI's specifications/recommendations and knowing that ADI simulator generates totally different loop filter component values for the 100kHz PLL comparison frequency. Mind that in DS2000 Rigol used the same 4360-7 PLL which is rated for 1.8GHz max and not for 2GHz.

Also there is weirdness in FFT for DC vs AC coupled channel input, with AC coupled being worse in noise, and FFT also has unknown spurs. But that may be a separate issue.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 08, 2014, 07:35:54 am
Can this be done without a hardware change - I personally doubt but that is IMHO.

Just curious: would that hardware modifications be limited to replacing passives with appropriate values (which is easy to do in the service center, and if one doesn't want to bother with sending the scope can do soldering himself) or the circuit itself is to be modified (meaning for clean solution without bodge wires and so it'll be required to change the whole board in the scope) ?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: nfmax on December 08, 2014, 08:12:26 am
I don't have one of these 'scopes, but I wonder if the PLL non-locking issue, which seems so obvious to some but it is clearly not present everywhere, arises at bottom from a bit of unauthorised 'equivalent' part substitution along Rigol's supply chain? Maybe the engineering prototypes all work just fine. It would explain the request for access to units known to suffer from the problem.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 08, 2014, 08:37:33 am
I don't have one of these 'scopes, but I wonder if the PLL non-locking issue, which seems so obvious to some but it is clearly not present everywhere, arises at bottom from a bit of unauthorised 'equivalent' part substitution along Rigol's supply chain? Maybe the engineering prototypes all work just fine. It would explain the request for access to units known to suffer from the problem.

Did i miss something or there's no reports about properly locked PLL in DS1000z series? I don't have issues with PLL because i'm using DS2000 series. We were just comparing behavior of this two guys because their PLL schematic is quite the same.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 09, 2014, 02:28:09 am
...
It looks like the ADC PLL is faithfully following the input clock.  No surprises here.
...

Just curious, if we saw a PLL with 500 MHz output locked to a jittery 125 MHz input, shouldn't a 100ppm error on input frequency lead to a 100ppm error on output frequency? Yet, we're seeing a 127 kHz side-peak on 125 MHz signal (100ppm frequency error) leading to a 125 kHz side-peak on 500 MHz (25 ppm). To be fair, I don't have any decent intuition on how jitter is supposed to look on spectrum analysers, but can someone explain how the frequency scale is being translated 375 MHz rather than scaled 4x here?

In general, jitter on a spectrum analyzer will appear as a widening of the main carrier frequency due to random noise or periodic influences.

My interpretation of the case we have here is that the jitter has at least some modulation components.  Those close-in peaks near the carrier are related to the *frequency* of the modulation (not the amplitude), like you would see in FM modulation.  It appears it has a modulation frequency involving 62kHz and 125kHz (and possibly others) with a small deviation.

Because the close-in peaks are related to the frequency of the modulation, it's why you also see them at the same spacing after the carrier has been divided by four from LCLK to FCLK.  For each divide by two you should also see them drop by 6dB, which is also the case here (11.99dB - almost too perfect...).

Maybe Bud or other reader has a further or different interpretation.  One thing for sure is the input clock shouldn't be doing this, but I don't see anything in the ADC output clocks that can't be explained.  That's why I say it's tracking the "garbage in".


If you're curious and looking for an intuitive feel, set up a signal generator with an FM input, maybe 10MHz carrier, 20kHz modulation, and 300Hz deviation, and feed it into a couple of cascaded flip flops each set up to divide by 2.  Look at the output on a spectrum analyzer or scope FFT.  It's pretty interesting to see what effects the modulation parameters have on the spectrum, and see how the division works.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 09, 2014, 03:57:28 pm
Did i miss something or there's no reports about properly locked PLL in DS1000z series?
I haven't seen any reports.  It's only easy to prove it's *not* locked with the 5us jitter.

Without access to the LOCK bit, it's harder to say it *is* locked unless you look at the clock directly on a spectrum analyzer, or indirectly by doing a long point FFT of a stable signal as I previously described.

If someone wants to create a quick program using one of the various packages that does a long point FFT (like 1 or 2Mpts), we could pass that around and get an idea which models do or don't have clock problems, including the DS2k series.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 09, 2014, 04:24:39 pm

Just curious: would that hardware modifications be limited to replacing passives with appropriate values (which is easy to do in the service center, and if one doesn't want to bother with sending the scope can do soldering himself) or the circuit itself is to be modified (meaning for clean solution without bodge wires and so it'll be required to change the whole board in the scope) ?

As far as the PLL is concerned, it is the loop filter components (3 caps, 2 resistors) that woul need to be replaced. I could tell now what they should be but the problem is with Rigol PLL programming. As i said a few posts back, they do not follow manufacturer's (Analog Devices) recommendations and program values in it that do not make sense. Based on information from ADI you cannot relay on the simulator if you do this. I used the ADI simulator when i built my PLL, as you can see it works perfectly, and i can tell what the loop filter should be but until Rigol reads the PLL datasheet and honors manufacturer specifications and does programming properly, the new loop filter will not work if i publish it.

In my opinion Rigol should redesign the PLL both programming and loop filter, and if this will require loop filter change  they should bite the bullet and recall the defective product for upgrade in service centers. Mind you my fellow EEBlogers, there is a product out there with the ABC and the holy grail of digitizing - ADC clock - being totally screwed.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 09, 2014, 04:37:30 pm
MarkL - nice idea and may be useful for checking other Rigol scope models
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: xnaron on December 09, 2014, 08:28:36 pm
MarkL - thanks a bunch for the work you have done, we are fortunate to have you here with all your nice test equipment, except the Rigol scope which is itself being under test.

So we can now say the RCC (Rigol Chaos Clock) is not limited to just channel input signal sampling and is propagated to the downstream bus, causing whatever damage. By other words, until Rigol delivers the proper fix,

YOU GUYS CANNOT TRUST YOUR RIGOL SCOPE

Such a fix would be a change that will get the ADF4360-7 PLL (ADC clock source) to generate the proper 1GHz signal. I have attached a side by side screenshots again what it is now and what it has to be. Can this be done without a hardware change - I personally doubt but that is IMHO.

Here is what the ADC datasheet says in regards to clock:

...The quality of the input clock is extremely important for high-speed, high-resolution ADCs
...If the clock is generated by other circuitry, it should be re-timed with a low jitter master clock as the last operation before it is applied to the ADC clock input
.

It's probably unlikely that Rigol will comment on any of this reverse engineering of their scopes.  The proof will be in whether the final firmware fixes the issue.  I am hopeful it will as I want to trust my Rigol scope.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 09, 2014, 08:37:28 pm
I am hopeful it will as I want to trust my Rigol scope.

Better to have second one just to be sure :)

And i also loved MarkL's idea. Unfortunately, i wouldn't have time for until next week, but then might try looking into it. No promises tho!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 09, 2014, 11:00:25 pm
And i also loved MarkL's idea. Unfortunately, i wouldn't have time for until next week, but then might try looking into it. No promises tho!

I just checked and it works fine to save large captures to the USB drive.  So you don't need to deal with the network or the scope plugged into a USB host and all the fun drivers that go with those.

Under "Acquire" you would set the scope to do 1.2MPts for a DS1054Z (or somewhere around that if other models have different lengths).  120k isn't enough, and any more than 1M or 2M doesn't provide additional information.  The scope needs to be in "Run" to change the record length.

Whatever stable input you're capturing, make sure it's also happening at the maximum sample rate of the scope (1GS/s for DS1054Z).

Under "Storage" select "Storage > Waves", and do the save.  I stopped the scope before doing the actual save, but I'm not sure that's necessary.

I'm certain I saw a posting by someone who developed a program that reads Rigol .wfm files but I can't find it at the moment.  For a quick and dirty hack to validate the data I just chopped the header information off the front and read the data bytes directly into octave (matlab).  The data bytes start at 0x0C7E for the files it made for me, but this is NOT clean, and NOT the right way to do it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: ted572 on December 10, 2014, 11:55:28 pm
And i also loved MarkL's idea. Unfortunately, i wouldn't have time for until next week, but then might try looking into it. No promises tho!
I'm certain I saw a posting by someone who developed a program that reads Rigol .wfm files but I can't find it at the moment.  For a quick and dirty hack to validate the data I just chopped the header information off the front and read the data bytes directly into octave (matlab).  The data bytes start at 0x0C7E for the files it made for me, but this is NOT clean, and NOT the right way to do it.

Try MATLAB release 7.5 R2007b or newer.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: EEVblog on December 11, 2014, 01:36:04 am
Well I was just about to do a video upgrading my unit and seeing what happens, but Rigol have pulled the firmware.
So won't be able to do jack before they release a new version, that includes finishing my review (supporters have already seen 1hr of footage).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Monkeh on December 11, 2014, 01:37:10 am
Well I was just about to do a video upgrading my unit and seeing what happens, but Rigol have pulled the firmware.
So won't be able to do jack before they release a new version, that includes finishing my review (supporters have already seen 1hr of footage).

If you would like a copy of the fabulously broken firmware, I do have one..

E: Eh, sent it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 11, 2014, 10:36:28 am
I applied the fix and it works fine on the MSO1074Z I have.

I did too, but as the other person said, the version says SP3, and every time it still detects the update file. Is this correct behavior?

Yes.

Yesterday, I had the beta firmware still on the USB, but for some reason it is not picking up the update as it did previously...  :-//

Is anyone getting this now?

This makes me wonder if the next firmware will even be detected... I hope they havent screwed something up big time.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RoTTe on December 11, 2014, 01:13:28 pm
Hi folks!

New unit, arrived today (the signal comes from a FE5680B 20MHz 2.8Vpp):

Model: DS1054Z
Software version: 00.04.02.SP3
Board Version: 0.1.1

The jitter from 5us is there. Not the worst case, but there. The AC thing too, is bad, but there is something weird there. If you touch the trigger level you can "clean" the signal, maybe I'm doing something strange but I just checking the whole thing step to step.



Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 11, 2014, 02:53:16 pm
Hi folks!

New unit, arrived today (the signal comes from a FE5680B 20MHz 2.8Vpp):

Model: DS1054Z
Software version: 00.04.02.SP3
Board Version: 0.1.1

The jitter from 5us is there. Not the worst case, but there. The AC thing too, is bad, but there is something weird there. If you touch the trigger level you can "clean" the signal, maybe I'm doing something strange but I just checking the whole thing step to step.

This actually looks pretty good to me.  Nothing like some of the other examples of 5us jitter with the released code.

Would you mind doing a 1.2MPt capture of that waveform, save it as a .WFM, and put it somewhere for me?  You can PM me with the drop URL.

In the absence of a generally available program, I'd like to try indirectly analyzing some of these sample clocks.  Anyone else who is still hanging out in this thread after 46 pages is welcome to do the same.  Sergey, Bud, poida_pie, ...

Please include what signal you're capturing, model, and HW/SW vers.  I'll post back to the thread with the long point FFT areas of interest.  Remember - it needs to be a stable source like a crystal oscillator, and taken at the highest possible sample rate of the scope.  A source anywhere from 10MHz to 100MHz would be fine.

EDIT: Actually, if you could include two different sources it would be better.  We can then rule out issues in the source (with a fair amount of certainty, anyway).

EDIT #2: Thinking about this a little more, the higher the frequency of the test source the better, if you have multiple choices.  For each decade away from the internal sample frequency, perturbations from the sample clock get buried another 20dB.  100MHz would make most anything stand out if you have it.  But I'll take anything.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RoTTe on December 11, 2014, 03:18:22 pm
This actually looks pretty good to me.  Nothing like some of the other examples of 5us jitter with the released code.

Would you mind doing a 1.2MPt capture of that waveform, save it as a .WFM, and put it somewhere for me?  You can PM me with the drop URL.

In the absence of a generally available program, I'd like to try indirectly analyzing some of these sample clocks.  Anyone else who is still hanging out in this thread after 46 pages is welcome to do the same.  Sergey, Bud, poida_pie, ...

Please include what signal you're capturing, model, and HW/SW vers.  I'll post back to the thread with the long point FFT areas of interest.  Remember - it needs to be a stable source like a crystal oscillator, and taken at the highest possible sample rate of the scope.  A source anywhere from 10MHz to 100MHz would be fine.

EDIT: Actually, if you could include two different sources it would be better.  We can then rule out issues in the source (with a fair amount of certainty, anyway).

The FE5680B is warming. I'll edit the post when I've the data.

Edit: PM sent.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 11, 2014, 05:21:53 pm
Ok, a couple of people sent me captures.  I'll edit and append to this post with more.  And I'll edit the post to get the images in-line with the comments (haven't done that before...)

A note on the plots:  It should be obvious x is frequency.  Y is in dB of the raw ADC units (0 to 255).  It's not calibrated to the vertical setting since we're only interested in the shape of the waveform and relative db of the peaks.


From pa3bca:
  Waveform 1: 10 MHz from a Rigol DG1032Z generator
  Waveform 2: 10 MHz from a GPS disciplined OCXO
  Firmware version is 00.02.03.SP5, no idea abt the HW board version.
  This 1074Z has NO 5us trigger issues!

Looks pretty clean to me too.

Waveform 1:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124003;image)

Waveform 2:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124005;image])


From RoTTe:
  The generator is a FE5680B, the 20MHz have some DC bias (2.30Vpp), and the 60MHz is a little attenuated (2.8Vpp).
  Model: DS1054Z
  Software version: 00.04.02.SP3
  Board Version: 0.1.1

So, this one's PLL is not locked, but the instability isn't too severe.  Note the 100kHz spacing originating from the PFD, which is what we should find in all the scopes running this version.

20MHz sine (stopped):
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124018)

60MHz sine (stopped):
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124020)


From nuno:

Scope: DS1104Z-S , sw 00.04.00

  16.wfm: 1 channel capture @ 1Gsps, source is 16.000 MHz crystal on AVR microcontroller, measured across the crystal's pins with the GND spring, channel with AC coupling (original signal has an offset)
  25.wfm: 1 channel capture @ 1Gsps, source is oscilloscope's own function gen, sine @ 25MHz 1Vpp

This 1104 looks fine to me.  The 16.wfm is a little noisy, but the main carrier does not appear to have any modulation in it.  25.wfm is also good, but it's probably using the same clock source internally for sampling and generation, and could have synchronized away any issues.  But since 16.wfm is ok, I think it's ok.

16.wfm:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124081)

25.wfm:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124083;image)


From Bud:
  DS2072A Hardware v2.0, Firmware 00.03.00.SP1

  F=280MHz via a 280MHz bandpass filter to reduce source spurious/harmonics
  Source 1: HP 8753C VNA (low phase noise)
  Source 2: HP 8656B signal gen

  Scope memory depth 1.4Mpts
  Sampling frequency 2Gsa/S

  Sergey's tests before showed anomalies dc vs ac coupling, so just in case I made two waveforms from 8753C

  The 280MHz frequency choice was just because I have a good bandpass filter for that frequency. But it is also close to the 300MHz scope bandwidth limit (in fact I measured 400MHz 3dB bandwidth on that scope).

These look like there might be a tiny bit of 200kHz modulation in the clock.  But I'm also noticing the close-ups of the main carrier show that there is a slight difference in the offset between the two sources which may imply it's in the source.

I'm undecided on this one.

Bud: Being a precision RF guy, you probably know these sources very well.  Your comments?  Have you looked at your Rigol's internal clock with a swept analyzer?

8656B_280MHz_0dBm_Dc_coupling:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124206;image)

8753C_280MHz_0dBm_ac_coupling:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124208)

8753C_280MHz_0dBm_dc_coupling:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124210)

8656B_280MHz_0dBm_Dc_coupling_closeup:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124212)

8753C_280MHz_0dBm_dc_coupling_closeup:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124214)

8753C_280MHz_0dBm_ac_coupling_closeup:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124216)


From leppie:

  DS1054Z - beta FW, mine like poda-pie's is very bad after beta FW, jitter goes away in offset intervals of ~33us (was 10us before beta FW)
  24Mhz crystal, no trigger offset

Only one capture provided.  I'm not sure without comparing against a second source.

Just kidding.  Wow, what can I say.  It's not even centered on 24MHz.  You win the award for best stegosaurus.

In measuring those modulation spikes they are 35.8kHz apart (almost 1/33us), but I'll bet they drift so the jitter offset is going to drift too.

24.wfm:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124220;image)


From poida_pie:

  signal source: Rigol DG1022, 20MHz sine, 1v p/p into 50 ohm terminated BNC at scope.
  Vertical gain 0.2V/div
  DS1054Z sample rate: 1G
  DS2072 sample rate: 2G

We have a runner up for instability.  I don't think it's quite as bad as leppie's because the modulation peaks are a little less broad.  But we're talking about the finer points of bad.

There is a different modulation frequency of 42.7kHz on this DS1054Z.  This is not surprising since when the PLL isn't locked variations in the loop filter components and the PLL itself are in play.  Temperature is going to matter too.

The DS2072 looks like fine with maybe a little more phase noise than the others, but that could be the source.

20Mhz_DS1054Z:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124231;image)

20Mhz_DS2072:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124233;image)


From sergey:

  Oscilloscope is DS2072
  Rigol DG1022A source
  Set up to 5MHz, HighZ. This all together with highZ input of the scope and genuine rigol coax cable shouldn't give any reflection issues.

As with the other DS2k series, the sample clock look fine to me.  5MHz is a little low for seeing perturbations in the clock (recall that for each decade away from the sampling clock we lose 20dB), but anything major will certainly show up.

Sergey sent me a 1.4Mpt and a 56Mpt capture of the 5MHz signal.  The 56Mpt capture provides resolution down to about 36Hz (and also took about a minute to process).  It's overkill for what we're looking for, but I thought it was interesting to include so people can observe how increasing the number of waveform sample points used in an FFT can dramatically improve the amount of detail you can see.

10us_1.4Mpts_2MHz_span (about the same span we've been using on the others):
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124248)

10us_1.4Mpts_120kHz_span:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124250)

10us_56Mpts_120kHz_span:
(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124252)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: ferdinandkeil on December 11, 2014, 06:30:05 pm
I'm certain I saw a posting by someone who developed a program that reads Rigol .wfm files but I can't find it at the moment.  For a quick and dirty hack to validate the data I just chopped the header information off the front and read the data bytes directly into octave (matlab).  The data bytes start at 0x0C7E for the files it made for me, but this is NOT clean, and NOT the right way to do it.

I think this is the program you were looking for: http://meteleskublesku.cz/wfm_view/ (http://meteleskublesku.cz/wfm_view/)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pa3bca on December 11, 2014, 06:33:17 pm
I think this is the program you were looking for: http://meteleskublesku.cz/wfm_view/ (http://meteleskublesku.cz/wfm_view/)
Only this program cannot read (my) 1074Z .WFM files. It gives an obscure error when I open a WFM file.
I have used it before but that was with .WFM files from my 2072A.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 11, 2014, 06:44:32 pm
I think this is the program you were looking for: http://meteleskublesku.cz/wfm_view/ (http://meteleskublesku.cz/wfm_view/)
Only this program cannot read (my) 1074Z .WFM files. It gives an obscure error when I open a WFM file.
I have used it before but that was with .WFM files from my 2072A.
I would be surprised if you used it with your DS2072A without modifying the header. He wrote that for DS1052E WFM files, which have quite different headers compared to the UltraVision formats (unless Rigol modified the DS2000 WFM format in a later version of the FW - which is always possible). I've been able to get it to work with the DS2000, but only after changing the header to emulate a DS1052E (that was a couple FW versions ago).
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pa3bca on December 11, 2014, 06:59:33 pm
Ha you are right. I get an "unknown trigger mode" error with a 2072 wfm.
My memory is failing  >:(  ,i probably used it with wfms from my DS1052E
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 11, 2014, 09:20:56 pm
From RoTTe:
 ..
So, this one's PLL is not locked, but the instability isn't too severe.  Note the 100kHz spacing originating from the PFD, which is what we should find in all the scopes running this version.

Looks pretty bad, the "classic" original PLL problem.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 12, 2014, 08:56:16 am
So, this one's PLL is not locked, but the instability isn't too severe.  Note the 100kHz spacing originating from the PFD, which is what we should find in all the scopes running this version.

So this 100KHz is something what exists in both 1000 and 2000 series.

Do you want me to do some wavwform captures from 2000 series for you btw?

EDIT: Well, more like a question if it's a waveform of the LOCK pin of the PLL needed or something else?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: RoTTe on December 12, 2014, 11:37:04 am
From RoTTe:
 ..
So, this one's PLL is not locked, but the instability isn't too severe.  Note the 100kHz spacing originating from the PFD, which is what we should find in all the scopes running this version.

Looks pretty bad, the "classic" original PLL problem.

Eh! It's better than my chinese multimeter!. And if you think that its bad wait to see the Atten 1102CML at the office, crappy as hell (all the GUI freeze at random intervals).

Now seriously, I bought this before this was known -for the general public- (two month of lead time). I'm tempted like a small child to broke the warranty sticker, solder four wires and plug the BusPirate or something like that and reprogram the PLL on the fly with the 5mA setting ( or whatever I want ). Two things stop me from doing that: One client hitting my door like Leonidas at 300 waiting for his PCBs and the lead time of another one if the fecal matter hits the fan with this new shinny and beauty thing (something can go wrong murphy said, and I need this NOW).

I'm thinking from another approach from the software side, but this need a lot of know how from firmware struct, and these things take time. I hope Rigol will solve this -from software-, If the worst case scenario is having to rebuild all PLL stage I'll do it. I love playing with these things.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 12, 2014, 01:07:47 pm
I think this is the program you were looking for: http://meteleskublesku.cz/wfm_view/ (http://meteleskublesku.cz/wfm_view/)

Well, only windows and no sources. Seems i'll still need to write my own reader as an evening project :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Michal_S on December 12, 2014, 01:49:19 pm
I think this is the program you were looking for: http://meteleskublesku.cz/wfm_view/ (http://meteleskublesku.cz/wfm_view/)

Well, only windows and no sources. Seems i'll still need to write my own reader as an evening project :)
Please do, if you can.
I've been trying to do something on my own, using pyRigolWFM sources as a base, and Hex Workshop for reverse engineering the new format. Vertical, horizontal scales, vertical offset, sample count, sampling rate, channel labels, samples were quite easy to find. However, this seems not enough to calculate the waveform from raw data. The origin of the raw data varies with vertical scale and offset settings (it's not always 127 as one might guess), and I don't know how to get this origin, for example.  I took a look at Rigol programming manual for DS1000Z, you can get YORIGin and other parameters necessary to calculate voltage waveform using SCPI commands. I tried to find the same numbers in the WFM file, but no success. If YOrigin, YRef, YInc are in the file, they are not there as simple float/uint values (as the other data that I already located are) :/ Maybe YOrigin can be derived from Vertical Scale and offset settings, but I think then only Rigol knows how...
As I'm heading for importing the data as digital data for import to Sigrok, I may settle on just using the RAW values directly, but of course it would be great to be able to calculate voltage values for other uses.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 12, 2014, 02:02:40 pm
I think this is the program you were looking for: http://meteleskublesku.cz/wfm_view/ (http://meteleskublesku.cz/wfm_view/)

Well, only windows and no sources. Seems i'll still need to write my own reader as an evening project :)
An evening? Good luck with that!  ;)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 12, 2014, 05:19:45 pm
I think this is the program you were looking for: http://meteleskublesku.cz/wfm_view/ (http://meteleskublesku.cz/wfm_view/)

Well, only windows and no sources. Seems i'll still need to write my own reader as an evening project :)
An evening? Good luck with that!  ;)

Given MarkL just makes a small binary edit and then presumably just reading the bytes, all one need to do is download some FFT lib and a graphing lib.

A few hours tops to code (for someone knowing what they doing), but there are probably tools that can achieve the same with minimal effort.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 12, 2014, 06:39:45 pm
Given MarkL just makes a small binary edit and then presumably just reading the bytes, all one need to do is download some FFT lib and a graphing lib.
That's all I'm doing.  I dump the hex of the file and find the start of the data by hand.  It's mostly at the same offset per model, but not always (probably depends on what people have set).  And sometimes there's a tail that needs to get chomped.

One byte per sample at 1GHz is how I've asked people to do the capture.  Done.

One potentially useful side effect of all this is that I will have a nice pile of captures from different model scopes.  If no one objects, I could make them available for testing for anyone developing a real program to read them and do plots, FFT, etc.  (I can't imagine anyone would object, but if someone doesn't want their capture shared please PM me.)

I have a few more captures people have sent me.  I'll get them added to the "clock analysis post" this afternoon.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 12, 2014, 06:45:29 pm
I have a few more captures people have sent me.  I'll get them added to the "clock analysis post" this afternoon.

 :-+

I hope mine is not nonsensical as you did not specify what timebase to use  :scared:
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 12, 2014, 07:27:59 pm
A few hours tops to code (for someone knowing what they doing), but there are probably tools that can achieve the same with minimal effort.

Did you not read the post above mine from Michal_S detailing the difficulties of cracking the format on the new Rigol WFM files? And he's hardly the only one working on it - I know other people that have been as well.

It's easy as pie to open a WFM file in a hex editor and extract the waveform data manually - and quite simple to take a CSV file and translate that into binary data. But, please, whip me up a UltraVision WFM reader by tomorrow that can extract ALL information (i.e. all DSO settings, raw waveform data, etc) across all the model lines - a few hours tops, right? I'd love to see that.  ;D
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 12, 2014, 07:36:41 pm
A few hours tops to code (for someone knowing what they doing), but there are probably tools that can achieve the same with minimal effort.

Did you not read the post above mine from Michal_S detailing the difficulties of cracking the format on the new Rigol WFM files? And he's hardly the only one working on it - I know other people that have been as well.

It's easy as pie to open a WFM file in a hex editor and extract the waveform data manually - and quite simple to take a CSV file and translate that into binary data. But, please, whip me up a UltraVision WFM reader by tomorrow that can extract ALL information (i.e. all DSO settings, raw waveform data, etc) - a few hours tops, right? I'd love to see that.  ;D

It could few hours to code yes. But first you need to understand the file format, that's obviously orders of magnitudes more than few hours.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: sergey on December 12, 2014, 07:39:27 pm
Well, only windows and no sources. Seems i'll still need to write my own reader as an evening project :)
An evening? Good luck with that!  ;)

Well, don't get it as if i promised something! :P But i will spend some time on this just because it's kind of interesting to learn something from the process. Anyway, *if* i get something in there, i'll report back in the eevblog forum.

Let's get back to the jitter issues now :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 12, 2014, 07:47:26 pm
It could few hours to code yes. But first you need to understand the file format, that's obviously orders of magnitudes more than few hours.
That was precisely my point. It's like saying it would only take 10 minutes to drive across town - if only we had some petrol.

Apparently it took Dexter - the guy who coded the original WFM Viewer (http://meteleskublesku.cz/wfm_view/) - some time to reverse-engineer the header fields of the earlier Rigol WFM format (from the DS1000E series). No one has done it yet for the UltraVision versions, so: no petrol.

Well, don't get it as if i promised something! :P But i will spend some time on this just because it's kind of interesting to learn something from the process. Anyway, *if* i get something in there, i'll report back in the eevblog forum.
Great, it's worth the effort - to the whole community.  :)  I have spent a bit of time deciphering (or trying to decipher) many of the different file formats - including .MSK, .TRC, .REF, and .WFM.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 12, 2014, 08:08:18 pm
That's all I'm doing.  I dump the hex of the file and find the start of the data by hand.  It's mostly at the same offset per model, but not always (probably depends on what people have set).  And sometimes there's a tail that needs to get chomped.

One byte per sample at 1GHz is how I've asked people to do the capture.  Done.
Did you not read the post above mine from Michal_S detailing the difficulties of cracking the format on the new Rigol WFM files?
Did you not read the post...? Let's not be dicks about it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 12, 2014, 08:21:16 pm
Did you not read the post above mine from Michal_S detailing the difficulties of cracking the format on the new Rigol WFM files?
Did you not read the post...? Let's not be dicks about it.

So, you start name-calling? And sorry - what exactly did I do? You responded to my post originally - not the other way round - and either you're still not getting the gist of the problem of writing an automated WFM reader in one evening:

It's mostly at the same offset per model, but not always (probably depends on what people have set).  And sometimes there's a tail that needs to get chomped.

...or you're just being.... well, let's say stubborn.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 12, 2014, 08:54:15 pm
Did you not read the post above mine from Michal_S detailing the difficulties of cracking the format on the new Rigol WFM files?
Did you not read the post...? Let's not be dicks about it.

So, you start name-calling? And sorry - what exactly did I do? You responded to my post originally - not the other way round - and either you're still not getting the gist of the problem of writing an automated WFM reader in one evening:

It's mostly at the same offset per model, but not always (probably depends on what people have set).  And sometimes there's a tail that needs to get chomped.

...or you're just being.... well, let's say stubborn.

Within that context, seeing you want all the bells and whistles and given paid at standard industry rate, a couple months.

Within the context of this thread. I stick to my estimate.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: marmad on December 12, 2014, 09:34:30 pm
Within that context, seeing you want all the bells and whistles and given paid at standard industry rate, a couple months.

Within the context of this thread. I stick to my estimate.

I'm not exactly sure we're talking about the same thing anymore, but I'll say just one last thing (then shut up about it):

I don't know how many UltraVision WFM files you've looked inside yourself - I've examined a hundred or so in the last couple of years, while trying to decipher Rigol's rather bizarre format (precisely why and by how much the data is offset from the header, etc) - with some help from EEVblog member Drieg, who was also looking into it - without any final success so far.

So if you believe you can whip out some software in an evening which JUST strips out the raw waveform data from any UltraVision WFM file - regardless of any settings on the DSO - please, do it. I don't think it's possible - but I would love to be proven wrong (and it would save me headaches in the future).  :)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pa3bca on December 12, 2014, 10:53:37 pm
If no one objects, I could make them available for testing for anyone developing a real program to read them and do plots, FFT, etc.  (I can't imagine anyone would object, but if someone doesn't want their capture shared please PM me.)
No objection especially not if the header is stripped off (the wfm output from my 2072A also contains the serial number and it imagines itself to be a 2302A which must be kept a secret  :-X)
A quick scan did not unearth anything resembling a serial number in the 1074Z wfm file, but who knows..
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 12, 2014, 11:55:42 pm
If no one objects, I could make them available for testing for anyone developing a real program to read them and do plots, FFT, etc.  (I can't imagine anyone would object, but if someone doesn't want their capture shared please PM me.)
No objection especially not if the header is stripped off (the wfm output from my 2072A also contains the serial number and it imagines itself to be a 2302A which must be kept a secret  :-X)
A quick scan did not unearth anything resembling a serial number in the 1074Z wfm file, but who knows..

Good point.  I don't like my serial numbers out there either.

But since I don't know anything about the header (I skip it completely), I don't know what else "interesting" might be in there.

I'll check with all contributors first if anyone asks for the file set.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 13, 2014, 04:01:51 am

From Bud:
  DS2072A Hardware v2.0, Firmware 00.03.00.SP1

  F=280MHz via a 280MHz bandpass filter to reduce source spurious/harmonics
  ..
These look like there might be a tiny bit of 200kHz modulation in the clock.  But I'm also noticing the close-ups of the main carrier show that there is a slight difference in the offset between the two sources which may imply it's in the source.

I'm undecided on this one.

Bud: Being a precision RF guy, you probably know these sources very well.  Your comments?  Have you looked at your Rigol's internal clock with a swept analyzer?


No I still have not opened my scope, not sure yet if to sell it as there are many little things, beside possible clock issues, that irritate me and create a perception of a Fisher-Price product (you folks who do not know who Fisher-Price is can look ip the name in Wiki). To name a few :

- the elusive 50 Ohm input issue when the inputs forget their 50 Ohm state on power up so the settings say they are on 50 Ohm when in fact they are not
- deactivation of measurements is awkward and done with separate buttons than activation
- saving waveforms all of  a sudden the filenames switch to Chinese with no option to switch to English
- tiny fonts in measurements
- lock ups when in setting internal date/time
- lock ups when the scope is connected  to LAN
- cumulative lock ups even with the scope not connected to LAN nor to USB but if it locked up once, it locks up again after a few min after a reboot, then keeps locking up with a smaller and smaller interval after each reboot until locks up almost instantly after reboot. This I found to be specific when the scope is configured to boot to the Last state vs Default state. The way to fix it was to set the scope in the menu to boot to Default state, which seemed to clear  the memory that stores the current corrupted settings or whatever, so the scope ran ok after booting to Default state. I now configured it again for Last state and so far so good but I feel that is again until something happens that will cause it to lock up and then again after each reboot it may have that issue.

I am too busy to leave with the above problems, I want to have an Instrument that I turn on and it works and I trust it. Cant say so about DS2072A.

But anyway , getting back to the waveforms. I do have a problem with the 100/200kHz peaks that seem to be PFD artefacts but they look too strong, being only 60dB down from the fundamental. Especially the 200kHz one. THis may indicate the loop filter sucks as it supposed to suppress  these artefacts that are way away from the loop filter cut-off frequency of about 3kHz.
Also I am worried what that 60kHz artifact is (the closest to the fundamental). It is only 45dB down which is pretty bad. Its origin is unknown but does not seem to come from the source as I used two different sources. So yes I feel like clock on DS2072a also should be checked with a spectrum analyzer.


Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: MarkL on December 13, 2014, 08:20:59 pm
But anyway , getting back to the waveforms. I do have a problem with the 100/200kHz peaks that seem to be PFD artefacts but they look too strong, being only 60dB down from the fundamental. Especially the 200kHz one. THis may indicate the loop filter sucks as it supposed to suppress  these artefacts that are way away from the loop filter cut-off frequency of about 3kHz.
Also I am worried what that 60kHz artifact is (the closest to the fundamental). It is only 45dB down which is pretty bad. Its origin is unknown but does not seem to come from the source as I used two different sources. So yes I feel like clock on DS2072a also should be checked with a spectrum analyzer.
I agree - it's not the sources.

At first I thought it might be the sources because the spectra changed when the source changed.  But the spectra are too similar to be a coincidence, and the difference is *very* small.  It may be from something as simple as the scope warming up while you changed the sources.

Can you see any cyclic delay jitter on this scope with these nice stable sources?  5us, 15us, etc (peaks of 100kHz sine)?  How about 7.3us, 21.8us, etc (peaks of 68.8kHz sine)?

They may be too far down to see visually in the time domain.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: David Hess on December 13, 2014, 08:27:14 pm
2) Since Rigol is in a jitter-fixing mode, could they perhaps also tackle the issue of the 8ns jitter on the Trigger Output? This bug makes the use of the Trigger Output problematic at best, and was first noticed on the DS2000 and reported about 2 years ago. It is also present on all of the MSO/DS1000Z models, as shown in my attached image (Channel 3 is the Trigger Output fed back into the DSO displaying the ~8ns of jitter).

I will be very surprised if this can be improved.  The timing resolution of the Trigger Output is going to be limited by granularity of the FPGA clock unless they added interpolation hardware.  Didn't Rigol suggest that this output was more useful for verifying the waveform acquisition rate than as a low jitter trigger output?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 14, 2014, 07:34:14 am
Can you see any cyclic delay jitter on this scope with these nice stable sources?  5us, 15us, etc (peaks of 100kHz sine)?  How about 7.3us, 21.8us, etc (peaks of 68.8kHz sine)?


I do not see a pronounced cyclic delay jitter, but as I set more uS delay , jitter increases to the point the trace becomes unusable, especially at >100MHz input frequencies. The trace becomes very shaky and I can see the spread in horizontal jitter if I turn on permanent persistence. DS2072A may need a good investigation. With lower frequencies the problem apparently is masked and not that obvious. Given your FFT results I am not surprised.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 14, 2014, 07:47:11 am
I will be very surprised if this can be improved.  The timing resolution of the Trigger Output is going to be limited by granularity of the FPGA clock unless they added interpolation hardware.

We have already seen Rigol Chaos Clock passing the child PLL in the ADC chip in DS1000 and getting to the downstream device bus. If, say, trigger timing is derived from that chaos clock, improving the clock should improve the trigger output.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: AlessandroAU on December 14, 2014, 11:04:25 am
Here's a small application that can read the entire memory buffer of the 1000z scopes and preform an FFT. You can also right click on the graphs and export them to excel/clipboard.

Edit: Updated Program to fix some errors
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 14, 2014, 11:29:00 am
Here's a small application that can read the entire memory buffer of the 1000z scopes and preform an FFT. You can also right click on the graphs and export them to excel/clipboard.

 :-+

Can I assume one needs the 32-bit version of the LabView runtime?

Update: Yes, that one works

Looking pretty good and seeing what MarkL has shown. Nice app!

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124487;image)

Looks nice with antialiasing turned on (in the app, not the scope) :)

(https://www.eevblog.com/forum/blog/eevblog-683-rigol-ds1000z-ds2000-oscilloscope-jitter-problems/?action=dlattach;attach=124511;image)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: AlessandroAU on December 14, 2014, 12:55:04 pm
Oops, Sadly yes you will need the runtime:

http://www.ni.com/download/labview-run-time-engine-2014/4887/en/ (http://www.ni.com/download/labview-run-time-engine-2014/4887/en/)

I can pack it with the exe as an install, but that brings it to 200mb anyway. So you might as well download the engine.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 14, 2014, 01:19:45 pm
Oops, Sadly yes you will need the runtime:

http://www.ni.com/download/labview-run-time-engine-2014/4887/en/ (http://www.ni.com/download/labview-run-time-engine-2014/4887/en/)

I can pack it with the exe as an install, but that brings it to 200mb anyway. So you might as well download the engine.

Can you modify this app? If so, can you allow the UI to be maximized so the charts zoom accordingly? With a splitter maybe?

I was also getting out of memory errors when capturing anything above 2Mpts.

Maybe the 64-bit runtime wont have this issue?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: AlessandroAU on December 14, 2014, 01:37:11 pm
Oops, Sadly yes you will need the runtime:

http://www.ni.com/download/labview-run-time-engine-2014/4887/en/ (http://www.ni.com/download/labview-run-time-engine-2014/4887/en/)

I can pack it with the exe as an install, but that brings it to 200mb anyway. So you might as well download the engine.

Can you modify this app? If so, can you allow the UI to be maximized so the charts zoom accordingly? With a splitter maybe?

I was also getting out of memory errors when capturing anything above 2Mpts.

Maybe the 64-bit runtime wont have this issue?

You can zoom/pan in on the charts with the tools underneath the graph (the three buttons).

Have you set the memory depth options correctly on your scope? (don't leave it on auto). Each of the memory depth settings works fine for me on a 1074.

Maybe a screenshot of the error? I think I've encountered it before, its driver/usb related and a reboot fixed it.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pa3bca on December 14, 2014, 02:03:59 pm
I can pack it with the exe as an install, but that brings it to 200mb anyway. So you might as well download the engine.
Unfortunately you have to create an account first before you can download the runtime. I hate that. Probably must supply all sorts of relevant and not so relevant personal info like shoe size and favorite coffee brew or whatever. (I know, I exaggerate).
So, if there would be any other way to download the runtime (that is legal of course)...
You app looks really very useful.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: AlessandroAU on December 14, 2014, 02:06:59 pm
I can pack it with the exe as an install, but that brings it to 200mb anyway. So you might as well download the engine.
Unfortunately you have to create an account first before you can download the runtime. I hate that. Probably must supply all sorts of relevant and not so relevant personal info like shoe size and favorite coffee brew or whatever. (I know, I exaggerate).
So, if there would be any other way to download the runtime (that is legal of course)...
You app looks really very useful.

http://bugmenot.com/view/ni.com (http://bugmenot.com/view/ni.com)

The first login works ;)
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: pa3bca on December 14, 2014, 02:13:36 pm
http://bugmenot.com/view/ni.com (http://bugmenot.com/view/ni.com)

The first login works ;)
Thank you Sir!
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 14, 2014, 03:03:45 pm
I was also getting out of memory errors when capturing anything above 2Mpts.
Have you set the memory depth options correctly on your scope? (don't leave it on auto). Each of the memory depth settings works fine for me on a 1074.

Maybe a screenshot of the error? I think I've encountered it before, its driver/usb related and a reboot fixed it.

1: Scope maxed out on memory, click capture, get this.
2: Click OK, get this.
3: Click OK, get this, the click capture, UI stuck.

BTW on my 2560x1440 screen the UI (graphs rather) is rather 'tiny'.

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: AlessandroAU on December 14, 2014, 03:52:02 pm
I was also getting out of memory errors when capturing anything above 2Mpts.
Have you set the memory depth options correctly on your scope? (don't leave it on auto). Each of the memory depth settings works fine for me on a 1074.

Maybe a screenshot of the error? I think I've encountered it before, its driver/usb related and a reboot fixed it.

1: Scope maxed out on memory, click capture, get this.
2: Click OK, get this.
3: Click OK, get this, the click capture, UI stuck.

BTW on my 2560x1440 screen the UI (graphs rather) is rather 'tiny'.

Looks like it is physically running out of memory, I've removed some of the more computationally hard parts of the code (the part it got stuck at) and added more memory options. How many points can you download now?

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 14, 2014, 05:13:02 pm
I was also getting out of memory errors when capturing anything above 2Mpts.
Have you set the memory depth options correctly on your scope? (don't leave it on auto). Each of the memory depth settings works fine for me on a 1074.

Maybe a screenshot of the error? I think I've encountered it before, its driver/usb related and a reboot fixed it.

1: Scope maxed out on memory, click capture, get this.
2: Click OK, get this.
3: Click OK, get this, the click capture, UI stuck.

BTW on my 2560x1440 screen the UI (graphs rather) is rather 'tiny'.

Looks like it is physically running out of memory, I've removed some of the more computationally hard parts of the code (the part it got stuck at) and added more memory options. How many points can you download now?

This one works all the way to 4M. At 5M, I get out of memory. I run Win7 64-bit and have 16GB RAM.

It is not the reading bit that seems to be a problem but the FFT bit. I will DL the 64-bit runtime and see if it works better.

Update: 64-bit driver is a no go, dont bother... app wants 32-bit driver.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 14, 2014, 09:53:58 pm
I would like to ask owners of Rigol DSO to review my Methodology of testing .
I am using the Passfail function to detect when there is an abnormal triggering.
I am inputting into Channel 1 a 200Khz Square wave
settings:
      Input coupling to AC
      Trigger coupling to AC
      Trigger level  to 300mV
      Time base to 10nSec/Div
      Persistence to infinite
DO a single trigger scan
Create a Mask from single scan
Run PassFail Test
The Pictures below show the Mask and 2 tests.
Is there anything more I should Set??
     
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 15, 2014, 08:07:20 am
Well I see a few people seen the previous post and NO comments.
Here is a test of a 15MHz sinwave for more than 0.5 Giga Waveforms and there is No Jitter Error
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 15, 2014, 08:18:08 am
Ok time to make a more interesting post
Here are 2 displays of the tests for Jitter
 1. No   Error  testing 20 Mega Waveforms
 2  827 Errors testing 10 Mega Waveforms
Only 1 DSO setting was changed and by only a relative small amount.!

I hope this will help Rigol narrow down the problem, and Address it if possible

Is it Jitter or just a fixed trigger position error?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 15, 2014, 08:24:55 am
Can you try the highest frequency that you can generate, close to the scope bandwidth limit? 15MHz is rather on the low side. The scope must perform up to the specs frequency limit, or it would not be a fair test.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 15, 2014, 08:57:23 am
Can you try the highest frequency that you can generate,
Good point Bud, how is this
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Bud on December 15, 2014, 09:19:18 am
Can you crank up the offset to 50...100uS and retest.
thks.
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: Teneyes on December 15, 2014, 10:00:27 am
Can you crank up the offset to 50...100uS and retest.
I assume you are stating Trigger Delay.
I also show 55uS Delay
Just 1,000,000 waveforms tested
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: AlessandroAU on December 15, 2014, 10:52:00 am
Ok the issues with the program should be fixed, it was running out of memory calculating waveform statistics, now it only uses the first 50k points to calculate waveform stats. I was also storing the waveform array with unnecessary precision, anyway it should be ok now.

Let me know of any bugs

Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: leppie on December 15, 2014, 10:58:07 am
Ok the issues with the program should be fixed, it was running out of memory calculating waveform statistics, now it only uses the first 50k points to calculate waveform stats. I was also storing the waveform array with unnecessary precision, anyway it should be ok now.

Let me know of any bugs

Thanks :)

My main issue is with the Labview Runtime actually uninstalling Ultra Sigma completely.

What should be selected in the install screen to not have this happen?
Title: Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
Post by: AlessandroAU on December 15, 2014, 12:41:09 pm
Ok the issues with the program should be fixed, it was running out of memory calculating waveform statistics, now it only uses the first 50k points to calculate waveform stats. I was also storing the waveform array with unnecessary precision, anyway it should be ok