EEVblog #683 - Rigol DS1000Z & DS2000 Oscilloscope Jitter Problems

[orin]

New FW - brief report.

My scope arrived back from its vacation in Beaverton with the new FW.  See attached screenshot.

Here is a summary of testing the 3 major problems.

1. Keyboard hang every other restart: Fixed
2. 5us delay jitter: Maybe fixed - see below.
3. AC trigger coupling jitter: Fixed.

The 5us jitter was worse than before when I first turned the scope on.  However, after a couple of minutes, I looked back and the jitter was gone.  I turned the scope off for a few minutes, turned it on and the jitter was back.  I could see it get better and finally 'lock'.

The attached picture is a 1MHz signal from an 8640B.  The FFT center frequency is 25MHz and 5MHz per division.  The signal's harmonics are all below -55dBc as measured on an 8568A spectrum analyzer, so down in the noise here.

That's all I had time for tonight.  I spent too much time fighting NI/Agilent VISA.

Orin.

[orin]

Jitter tests from this morning:

jitter.png was pretty much just after turning the scope on.

After about five minutes, the jitter vanished, giving no_jitter.jpg

Temperature about 15 deg C.

Edit: vertical scale is really 0.5V/div.  It had defaulted to a 10X probe and no probe was involved, signal is 10MHz from a GPSDO with 50 ohm through terminator.

[Bud]

After about five minutes, the jitter vanished, giving no_jitter.jpg

This is a sign that the PLL is unstable.

Sorry to say your scope is still defective. What and when may happen would probably be subject to changes with temperature, humidity, components aging and who knows what else.

[tautech]

After about five minutes, the jitter vanished, giving no_jitter.jpg

This is a sign that the PLL is unstable.

Sorry to say your scope is still defective. What and when may happen would probably be subject to changes with temperature, humidity, components aging and who knows what else.

@ Bud
How much tolerance has Rigol in component value selection to get the PLL sorted?
Is the range of values within the normal +-% tolerance of components around the PLL or have they just got the basic values wrong?
Sure we would normally use NPO here, maybe they didn't?

[orin]

Jitter tests from this morning:

jitter.png was pretty much just after turning the scope on.

After about five minutes, the jitter vanished, giving no_jitter.jpg

Temperature about 15 deg C.

Edit: vertical scale is really 0.5V/div.  It had defaulted to a 10X probe and no probe was involved, signal is 10MHz from a GPSDO with 50 ohm through terminator.

would that process of jitter to no_jitter be repeated again after your scope is cooled? (or maybe, influence it by opening it and force cooling it further with a fan?)

It repeats.  I saw the same last night.  I turned the scope off overnight, then took the attached screenshots after turning it on this morning.  Given the times of my posts, about 8 hours 'cooldown'.

[rf-loop]

Jitter tests from this morning:

jitter.png was pretty much just after turning the scope on.

After about five minutes, the jitter vanished, giving no_jitter.jpg

Temperature about 15 deg C.

Edit: vertical scale is really 0.5V/div.  It had defaulted to a 10X probe and no probe was involved, signal is 10MHz from a GPSDO with 50 ohm through terminator.

would that process of jitter to no_jitter be repeated again after your scope is cooled? (or maybe, influence it by opening it and force cooling it further with a fan?)

It repeats.  I saw the same last night.  I turned the scope off overnight, then took the attached screenshots after turning it on this morning.  Given the times of my posts, about 8 hours 'cooldown'.

What I have tested DS1074Z, delay jitter is temperature dependent (but I have not tested what component specially (I do not want open it). I have tested it many times and it is fully repeatable.  (this individual scope do not have "5us" jitter what discussed more. Trig AC coupling jitter is sama as most have here.

Start cold, jitter. Continue warms up, less and less until no visible jitter and after then agen jittering start agen slowly rise when scope continue warm up.   

[Bud]

How much tolerance has Rigol in component value selection to get the PLL sorted?
Is the range of values within the normal +-% tolerance of components around the PLL or have they just got the basic values wrong?
Sure we would normally use NPO here, maybe they didn't?

No it is not component values tolerance issue, as you said they got the basic values wrong.

The worst problem that I see is they did not follow the manufacturer's recommendations, they even did not stick to the datasheet, why is I have no idea. Imagine yourself designing something, you select a part and the part manufacturer says - we make it easier for you, we have done extensive testing in the Lab an we have a reference design you can use. We have a set of recommended settings and that will guarantee the part will perform to specification. Noone knows our part better than us, the manufacturer. We have a simulator that you can use, here it is, take it, just run it and you will have your design in less than 10 minutes and it will guarantee to work. And you say like "Meh, I'll do it my way, have no idea how yet but will try random values until I get bored and then the heck with it as long as the device appear to be working".

Show a screenshot of their ADC clock (page 19 of this thread) to any engineer familiar with ADC applications and watch his reaction:
  

[tautech]

How much tolerance has Rigol in component value selection to get the PLL sorted?
Is the range of values within the normal +-% tolerance of components around the PLL or have they just got the basic values wrong?
Sure we would normally use NPO here, maybe they didn't?

No it is not component values tolerance issue, as you said they got the basic values wrong.

The worst problem that I see is they did not follow the manufacturer's recommendations, they even did not stick to the datasheet, why is I have no idea. Imagine yourself designing something, you select a part and the part manufacturer says - we make it easier for you, we have done extensive testing in the Lab an we have a reference design you can use. We have a set of recommended settings and that will guarantee the part will perform to specification. Noone knows our part better than us, the manufacturer. We have a simulator that you can use, here it is, take it, just run it and you will have your design in less than 10 minutes and it will guarantee to work. And you say like "Meh, I'll do it my way, have no idea how yet but will try random values until I get bored and then the heck with it as long as the device appear to be working".

Show a screenshot of their ADC clock (page 19 of this thread) to any engineer familiar with ADC applications and watch his reaction:
  

I had been watching your input and  that Rigol had not implemented the ADC correctly as you have identified some time back, and as new units display the same problems wondered again how close they were to getting it right.
Seems they are miles off by your analysis and I suspect you sometimes feel like a lone voice in the wilderness.
If they finally get it right, one would hope they send you a freebie for sticking your neck out.
Stick to your guns Bud, Test Equipment quality, or lack of, is of great concern.

[orin]

Test for Teneyes.

This is the GPSDO output, nice fast edge, a bit of ringing (don't know where that is coming from yet, I have to get the active probe out).  AC trigger coupling, 5uS delay, 0.021V position.  Temperature 15 to 16 deg C.

I'll leave it running.

[RigolTechUSA]

Thanks again to all the engineers, beta testers, customers, community members, and worldwide Rigol team members who have contributed to the discussion, validation, and solutions over the last month for the MSO/DS1000Z and MSO/DS2000A FW updates that we are now ready to release. It has been a great example of working together to make instruments even better. Thanks also for your patience as we worked through the proper process for evaluating, updating, and testing solutions that work for all of our customers. You can now find the firmware updates here:

MSO/DS1000Z Firmware

 MSO/DS2000A Firmware

Feel free to update at your convenience and let your local Rigol office know if you have any questions, issues, or problems. Happy New Year!

[leppie]

Thanks again to all the engineers, beta testers, customers, community members, and worldwide Rigol team members who have contributed to the discussion, validation, and solutions over the last month for the MSO/DS1000Z and MSO/DS2000A FW updates that we are now ready to release. It has been a great example of working together to make instruments even better. Thanks also for your patience as we worked through the proper process for evaluating, updating, and testing solutions that work for all of our customers. You can now find the firmware updates here:

MSO/DS1000Z Firmware

 MSO/DS2000A Firmware

Feel free to update at your convenience and let your local Rigol office know if you have any questions, issues, or problems. Happy New Year!

You kept the promise ;p

Bit drunk to try it out now. Will report back after a few days recovery.

[orin]

This is the GPSDO output, nice fast edge, a bit of ringing (don't know where that is coming from yet, I have to get the active probe out).  AC trigger coupling, 5uS delay, 0.021V position.  Temperature 15 to 16 deg C.

Thanks Orin
 Did you check what version of FW that is on your DSO?

 If in fact your DSO was set to AC triggering and there is NO Offset then I think you have a new version of FW.

As your Calibration is different , Could you please try AC input and AC trigger at 200Khz, and slowing move vertical position to see if there is any occurence of an error.
The error I see is Very Rare and not so much a jitter but a Offset of 8nS. (1 in 10,000)

Up to a few minutes ago, I probably had the newest version of the FW in the wild: 00.04.02.SP4 (see post #853 in this thread).  But I see links to new firmware were just posted by RigolTechUSA.

200 KHz and a fast rise time is more difficult.  I'll have to use the ADCMP580 setup which will have a lower pk-pk voltage.  With a bit of luck, I'll try tomorrow.

Orin.

[Teneyes]

firmware updates here:
MSO/DS1000Z Firmware
 MSO/DS2000A Firmware

Thank you , Chris and Rigol support 

As we go forward with this new Firmware . I suppose if a new bug is observed then a New Forum will be opened , so that we are All working together from the same 'Base FW' to improve the Rigol DSO.

Happy New Year to All

[Monkeh]

Thanks again to all the engineers, beta testers, customers, community members, and worldwide Rigol team members who have contributed to the discussion, validation, and solutions over the last month for the MSO/DS1000Z and MSO/DS2000A FW updates that we are now ready to release. It has been a great example of working together to make instruments even better. Thanks also for your patience as we worked through the proper process for evaluating, updating, and testing solutions that work for all of our customers. You can now find the firmware updates here:

MSO/DS1000Z Firmware

 MSO/DS2000A Firmware

Feel free to update at your convenience and let your local Rigol office know if you have any questions, issues, or problems. Happy New Year!

Please be so kind as to provide a precise changelog and a downgrade path should it make the issues worse again.

[miguelvp]

Biting the bullet here and updating as we speak, CH1 is still flashing and I hope I don't loose power during the update since I didn't have a UPS to hook it up to.

Longest 5-10 mins ever!


Edit: all lights up, so it's done, btw DS2000 series here.

[miguelvp]

I did never upgraded to a version that had CAN bus decoding and this one doesn't have it either or it doesn't show up in my menu, since I have no need for it I don't care, but if you do, be aware that it could take out your CAN decoding.

Here is the new version installed:


AC trigger coupling on the 1KHz test signal doesn't happen, but I don't have time to test further with the New Year coming along.

One thing is that my DC triggering on the test signal doesn't trigger until i'm at 200mV, at 180mV it doesn't lock, that's on a 3V PP signal.

[poida_pie]

The new firmware for the DS1000Z series does fix the jitter problem on my DSO.
See the two FFT. The first is what the jitter plagued PLL produced from the beta f/w
The second is what is produced now from the f/w supplied by Rigol.

software version now reports as 00.04.02.SP4
And the counter is accurate too, it shows 20.0002MHz for an input of 20MHz
I showed in past posts here that when the PLL was unlocked, the counter shows about 19.7MHz
Much better, Rigol.

[miguelvp]

Weird, I did put my USB device back and it didn't recognize it, had to reboot the scope but it's all good now.

Here is the DC coupling at 200mV


and at 180mV not locking


I'm going to see if I can download the previous GEL file to downgrade it to see if that was happening before.


Edit: It seems it only recognizes one insertion of the USB thumb drive, once I take it out it won't  recognize a subsequent insertion.

[miguelvp]

Testing downgrade to 03_01_00_04 first then I'll reupgrade and do the self cal.

[miguelvp]

Downgrade worked:



Not sure why it has the date on the manufacturer instead.

I still can't see the CAN option on decoding but maybe I'm doing something wrong or not supported on non A models.

Also the reinsertion of the USB thumb drive problem still persists, I used to be able to insert the drive more than once before as far as I recall, so not sure what firmware broke that.

I'll re-upgrade and do a self cal.

[miguelvp]

Still doesn't fully lock at 140mV on chan 1 it locks at 160mV, not sure what it was before the upgrade since I never did an exhaustive check.

But that's only on rising edge, on falling edge it triggers fine.

On chan 2 it locks at 200mV on rising edge, works fine on falling edge as well.

Will do a Storage Default and self cal again after warming up a bit.

Edit: Reinsertion problem of USB thumb drive (not detecting it a 2nd time) persists still.

[miguelvp]

After Storage->Default and Utility->Self Cal the problem with DC triggering locking on positive edge persists. Maybe it was there all along.

The USB drive problem is a concern as well, I used to leave the scope on and take screenshots, copy to PC then took more screenshots, etc, now I won't be able to do that anymore. I can always take all I need then copy them so not a big deal.

[miguelvp]

On AC coupled trigger.

If I lower the trigger threshold to less than -1.24V it looses lock, if above 1.74 it looses lock.

Not sure what that means since on AC lock it should check nor it displays the arrow for the lock level. But the signal being 3V PP you will think it would be -1.5 to 1.5 to lock it.

Maybe that's related to the DC locking or just to many pre new year's drinks

[Orange]

Still doesn't fully lock at 140mV on chan 1 it locks at 160mV, not sure what it was before the upgrade since I never did an exhaustive check.

Do you have 'Noise reject' ( trigger menu, settings) switched on ?

[leppie]

The new DS1000Z FW fixes my extreme jitter issues too 

Update:

The scope would not detect new FW on the USB stick at first. I formatted the stick and put only the FW file on it, then it picked it up. Perhaps it had an issue with a file present on the USB stick?