Author Topic: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems  (Read 409930 times)

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Offline i4004

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #425 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

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!
« Last Edit: November 22, 2014, 07:24:05 pm by i4004 »
 

Offline marmad

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #426 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.
« Last Edit: November 22, 2014, 09:07:20 pm by marmad »
 

Offline leppie

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #427 on: November 22, 2014, 08:36:50 pm »
the true resolution of the ADC is 256 bits
lol no  :palm:
 

Offline i4004

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #428 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.
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #429 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?
 

Offline Dave Turner

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #430 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'.
 

Offline marmad

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #431 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.
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #432 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!
 

Online Bud

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #433 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.
Facebook-free life and Rigol-free shack.
 

Offline MarkL

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #434 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.
 

Offline Fenichel

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #435 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.
 

Offline rs20

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #436 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...
 

Offline i4004

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #437 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...
« Last Edit: November 22, 2014, 11:16:01 pm by i4004 »
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #438 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.   :-//
« Last Edit: November 23, 2014, 12:08:03 am by jkrichards »
 

Offline Fenichel

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #439 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
  • 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.
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #440 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)
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #441 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.
 
 

Offline rs20

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #442 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.
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #443 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.
« Last Edit: November 23, 2014, 01:30:43 am by jkrichards »
 

Offline rs20

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #444 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.
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #445 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.
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #446 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.
 

Offline nuno

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #447 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.
« Last Edit: November 23, 2014, 03:21:00 am by nuno »
 

Offline jkrichards

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #448 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?
« Last Edit: November 23, 2014, 03:38:02 am by jkrichards »
 

Offline marmad

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Re: EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems
« Reply #449 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.
 


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