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Title: Internal jitter in DSO4202C oscilloscope [Print this page]

Author: Sead Time: 2019-7-18 03:53
Title: Internal jitter in DSO4202C oscilloscope
Edited by Sead at 2019-8-5 04:20

Hello there,

I bought recently a new DSO4202C oscilloscope. The product looks quite good and all functionalities are

good except taht on the higher frequencies the input signals are presented somewhat distorted and with
considerable jitter.

The same input signals are presented on the Keysigh/HP oscilloscope clear and without the jitter.

Does someone experience similar problems and can give me useful hints on how to get around this?

Thanks in advance
Sead

Author: Sead Time: 2019-8-5 04:25
Edited by Sead at 2019-8-5 04:29

Please see my previos post. Enclosed is the screen shot of signall jitter. Does someone have similar experiences?
[attach]3051[/attach][attach]3051[/attach]

Author: OASJ2YSeeEhBQo1 Time: 2019-8-6 05:45
Yes, unfortunately it is normal with Hantek's scopes, specially at higher frequencies. Try to use average mode to see if you can get a cleaner waveform. Test using 16 samples and see if it is good enough. Increasing the number of samples will slowdown your oscilloscope's response drastically.

Author: TMG Time: 2019-8-7 04:09
Hi Sead

What high frequency do you mean?

You can check if probe cable are straight not twisted with others or create coil turns. If you touch by hand cables also you can affect signal that you observe.
If you are able to use probe from Keysigh/HP scope with Hantek? Check if is better or not.

I've checked DSO4254C with TDS 620A and can't see significant differentials. Only when i touch cables or twist them. Test frequency 25 MHz. I don't have that big jitters as you but i don't know what was you signal frequency.

Author: OASJ2YSeeEhBQo1 Time: 2019-8-8 00:57
I think you need to go higher in frequency to see this feature. Above 40MHz if I recall.

See another picture here at 70MHz for reference: https://www.eevblog.com/forum/te ... 2089738/#msg2089738

Author: Sead Time: 2019-8-9 23:44
Hi TMG,

Thanks for your reply. I used my 50 MHz reference with -10 dBm clean sinus output . Checked that also with 100 MHz oscillator with the same results. The 50 MHz signal appears stable and clean on a HP 100 MHz oscilloscope.

Kind regards
Sead

Author: Sead Time: 2019-8-9 23:54
Edited by Sead at 2019-8-10 03:55

Hi OASJ2YSeeEhBQo1,

Thank you very much. Does that mean that the measurements of the signal rise-times, amplitudes and frequency are inaccurate? I mean if the oscilloscope is averaging signal with the jitter introduced by itself, than the measurements of input signal are inaccurate. I do not have such problems with my 100 MHz scope from HP.

Kind regards
Sead

Author: wjw Time: 2019-9-25 22:04
I have noticed the same problem when I looked at a 21 MHz sinewave. I compared it to a Rigol oscilloscope, and I don't see the jitter.

Author: wangshuang Time: 2019-9-29 16:51
please downlown the latest firmware in Hantek homepage and update the system.
http://www.hantek.com.cn/en/ProductDetail_3_4163.html

Author: Sead Time: 2019-9-30 21:46

wangshuang replied at 2019-9-29 16:51
please downlown the latest firmware in Hantek homepage and update the system.
http://www.hantek.com. ...

Hello Wangshuang,

I updated the system with the latest firmware as you suggested, but no improvement.
This fault makes all measurements questionable and as far as I can see it is present by other users as well. Many of them are possibly not aware of this.

Regards Sead

Author: Sead Time: 2019-9-30 22:05
On 30.09.2019 I did firmware upgrade to sw version 3.5.0(190613.0) hoping that the internal jitter issue in my DS4202C oscilloscope will be resolved.As you can see from the enclosed photo, this was not the case - the jitter is still prersent and influences all measurements (frequency, amplitude,
period, rise- and fall-times etc).
[attach]3178[/attach]

Questions:
- have you experienced such behavior on yours DSO4202C oscilloscopes?
- does someone knows what is the problem and how this can be eliminated?
Thanks in advance.
Sead

Author: OASJ2YSeeEhBQo1 Time: 2019-10-1 06:03
Try to use average mode in the Acquire menu button.

Author: Sead Time: 2019-10-2 15:24
Edited by Sead at 2019-10-2 15:43

OASJ2YSeeEhBQo1 replied at 2019-10-1 06:03
Try to use average mode in the Acquire menu button.

Thanks, I did it. The waveform is changing amplitude and phase considerably from one screen to another, I assume, due to averaging ecffect. I performed Pass/Fail Test and it looks miserable. Any other idea?

Author: Sead Time: 2019-10-2 15:36
I performed Pass/Fail Test and it looks like this:
[attach]3180[/attach]

How can I interpret this? Does it means that the Hardware is affected?

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