scope jitter

John Larkin · 2016-04-16T01:04:02+00:00

Here are two rising edges from a digital delay generator, programmed 5.5 ns apart. The scope is set for 10 second persistance. The scope is triggering on the ch 1 input, halfway up. The sweep speed is maxed at 2 ns per division. Digital scopes used to have a full sample of p-p jitter. This one shows no visible jitter on the ch1 trace, and hardly any on ch2. I'm guessing that the trigger is really software, based on the reconstructed (software lowpass filtered) waveform. It's impressive, however they do it. If I move the ch1 input to the AUX connector and trigger external, I see a full ns of p-p jitter on the ch2 rising edge. That means that the external trigger input is probably a classic comparator, and it's not synchronized to the 1 GHz sampling clock, and there's no attempt at interpolation. Other scopes may do the external trigger thing better. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com

Apr 16, 2016 41 Replies

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Lasse Langwadt Christensen 10 years ago

Den fredag den 22. april 2016 kl. 10.46.42 UTC+2 skrev krw:

when I was at a big American company, they were smart enough to know that OS updates and service packs etc. didn't always play nice with tools So engineering and production had a bit of leeway

-Lasse

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krw 10 years ago

Not so in my big, not so American, company. As long as we're connected to the Intranet, we're under the same rules as everyone else.

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