Author Topic: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems  (Read 399368 times)

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Offline leppie

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #50 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 onwards. Nasty stuff.
 

Offline Monsterhero

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #51 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.
« Last Edit: November 14, 2014, 05:09:51 pm by Monsterhero »
 

Offline TMM

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #52 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.
« Last Edit: November 14, 2014, 05:21:38 pm by TMM »
 

Offline SiC

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #53 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.
 

Offline mikeselectricstuff

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #54 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.

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Offline electronic_eel

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #55 on: November 14, 2014, 05:15:51 pm »
Watch from 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.
« Last Edit: November 14, 2014, 05:27:27 pm by electronic_eel »
 

Offline electronic_eel

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #56 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.
 

Offline leppie

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #57 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 :(
 

Offline pickle9000

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #58 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.
 

Offline TMM

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #59 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.
 

Online hans

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #60 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
« Last Edit: November 14, 2014, 05:45:37 pm by hans »
 

Offline Arch

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #61 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
 

Offline jnissen

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #62 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.
« Last Edit: November 14, 2014, 05:53:59 pm by jnissen »
 

Online dr.diesel

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #63 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


Offline leppie

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #64 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)
 

Offline nixfu

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #65 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.

« Last Edit: November 14, 2014, 06:13:11 pm by nixfu »
 

Offline janengelbrecht

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #66 on: November 14, 2014, 06:11:06 pm »
Pretty happy now ive got the DS1052E from Rigol with no issues at all :P

Offline David Hess

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #67 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.
 

Offline HexfeT

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #68 on: November 14, 2014, 06:21:24 pm »
DS1054Z
Software version: 00.04.01.SP2
Board version: 0.1.1

Normal


AC Coupled


5us Offset
 

Offline mikeselectricstuff

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #69 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.
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Offline dave3533

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #70 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
« Last Edit: November 14, 2014, 06:52:41 pm by dave3533 »
 

Offline pciebiera

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #71 on: November 14, 2014, 06:47:28 pm »
DS2072A
S/W: 00.02.01
H/W: 2.0

DC


AC


Trigger on rising and falling
 

Offline DEHiCKA

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #72 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  ;)
« Last Edit: November 14, 2014, 06:57:39 pm by DEHiCKA »
 

Offline RRobot

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #73 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).
« Last Edit: November 14, 2014, 07:30:27 pm by RRobot »
 

Offline DeepSOIC

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #74 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
 


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