ETS trace may lose timing accuracy if 3+ channels in use

lab!fyi · Post by **lab!fyi** » Tue Sep 04, 2018 7:36 am

ETS trace develops jitter if more than 2 channels enabled, with exception: Signal on A,B stays ok when enabling more channels, however signal timing on A,C or A,D breaks when enabling more channels. Possibly there are more ok/notok combinations. Jitter is huge for 20GS/s operation and makes measurement unusable.

Env: PS 6.13.6.3775; PS 2408B; HW 1; driver 2.1.0.570; FW 1.3.3.0 / 1.0.51.0

lab!fyi · Post by **lab!fyi** » Wed Sep 05, 2018 2:46 pm

Any feedback? Is it known bug? Needs further investigation? Checked for same issue on PS 6000 scope - luckily not present.

Hitesh · Post by **Hitesh** » Wed Sep 05, 2018 3:59 pm

Hi lab!fyi,

Would it be possible for settings or data files for the two scenarios please? We can then investigate this using the files provided.

What are the input signals on the scope?

Thanks,

lab!fyi · Post by **lab!fyi** » Wed Sep 05, 2018 5:33 pm

Hi, here is picture of physical setup and two PSDATA files with 32 frames buffered for both cases. Only difference between jitter / no jitter scenarios is switching ON/OFF not connected Ch C (or B).

Hitesh · Post by **Hitesh** » Thu Sep 06, 2018 2:44 pm

Hi lab!fyi ,

We have tried to replicate your setup as closely as we can, including using a fast edge, but we have so far been unable to repeat the issue.

Below is a screenshot using a slightly modified version of your settings and it shows a reasonably stable signal:

: ETS mode capture with 3 channels

We will try to investigate further, but if there is any further information about your setup, please do let us know.

Regards,

lab!fyi · Post by **lab!fyi** » Thu Sep 06, 2018 4:45 pm

Hi, thanks for effort. I did sent additional info to support e-mail since attachments too big to fit here.

Hitesh · Post by **Hitesh** » Fri Sep 07, 2018 8:24 am

Hi lab!fyi,

Thank you for sending the e-mail. We will respond after further investigation.

Regards,

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ETS trace may lose timing accuracy if 3+ channels in use

ETS trace may lose timing accuracy if 3+ channels in use

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Re: ETS trace may lose timing accuracy if 3+ channels in use

Re: ETS trace may lose timing accuracy if 3+ channels in use

Re: ETS trace may lose timing accuracy if 3+ channels in use

Re: ETS trace may lose timing accuracy if 3+ channels in use

Re: ETS trace may lose timing accuracy if 3+ channels in use