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From Oscilloscope to Wireshark: A UDP Story (2022)

mattkeeter.com

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Re: From Oscilloscope to Wireshark: A UDP Story (2022)

#31

Post by blindseeker »

wila wrote: post #28
blindseeker wrote: post #27

University professor here: showing and decoding wire signals has become a staple in my teaching - very effective, eye-opening even for students that find the OSI layers too abstract to grasp on paper. Btw, I’m using this nice demo board (I’m not affiliated with the brand): https://www.batronix.com/shop/demoboards/Batronix-MSO-Demo-B... …typically we decode I2C. Oh, I‘ve equipped the lab with all kinds of oscilloscope…

Interesting. Do you happen to know if that batronix board useful to have even if you have a Rigol DHO 924S without the logic probe (PLA2216)?

Yes, it’s absolutely useful. You need the logic probe (which I do have, but never use in „standard“ teaching) only if you plan (or need) to monitor more input signals than the analog ones on the scope.

In fact, to demonstrate the very physical foundation of digital computing, it is very useful to use the analog inputs and zoom all the way in to see the slight imperfections in signal transmission.

Re: From Oscilloscope to Wireshark: A UDP Story (2022)

#33

Post by Junk_Collector »

cesaref wrote: post #13
Junk_Collector wrote: post #11

Earlier quoted context omitted.

If you are an absolute nutcase, you could characterize a set of line stretchers and a multiplexer on a high end VNA then offset the inputs of the 4 channels on that UXR with them, take a capture and finally rebuild a 1TSamp/s signal out of the 4 results. You have to have the 240V model of the scope to run all four channels at full rate (110GHz) though.

The older Tektronix TDS540 series did this, but at much lower rates as was common in those days though. Internally there are differential feeds from the very beautiful hybrid ceramic input boards to 4 DACs, with some clever switching so that a single input can be sampled by all 4 DACs with a suitable offset to create 4x the sample rate when running with all 4 inputs. The calibration procedure on the scope fiddles wit…

Yup, a lot of scopes actually did this internally and some still do. It's part of why some scopes lose half their BW when you go from 2 ports to 4 ports (some go the other direction and run multiple ports on one very fast ADC), they split the digitizers. It's just very very difficult to keep it working external to the box mainly because of line drift.

Re: From Oscilloscope to Wireshark: A UDP Story (2022)

#34

Post by wila »

blindseeker wrote: post #31
wila wrote: post #28

Earlier quoted context omitted.

Interesting. Do you happen to know if that batronix board useful to have even if you have a Rigol DHO 924S without the logic probe (PLA2216)?

Yes, it’s absolutely useful. You need the logic probe (which I do have, but never use in „standard“ teaching) only if you plan (or need) to monitor more input signals than the analog ones on the scope. In fact, to demonstrate the very physical foundation of digital computing, it is very useful to use the analog inputs and zoom all the way in to see the slight imperfections in signal transmission.

Thank you!

Re: From Oscilloscope to Wireshark: A UDP Story (2022)

#35

Post by KK7NIL »

HunterWare wrote: post #7
HunterWare wrote: post #6

Earlier quoted context omitted.

Looks like max 50GS/s per their site. That also looks reasonable with the screenshot they have in the article showing 1ns / div horiz. But clarity on the data would be lovely. =)

Actually I take it back: For the series 6B spec page... Real-time: 50 GS/s (2 channels), 25 GS/s (4 channels), 12.5 GS/s (> 4 channels) Interpolated: 2.5 TS/s

Yeah, I used to work at Tektronix, this looks like an A unit.

Also, the 50GS/s is actually more like 25GS/s as it has a Nyquist frequency of 12.5 GHz. This is because they take 2 samples at the same time, instead of 180 degrees out of phase. I wish they had made that clearer to customers, it felt misleading to some.

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