Quote:
Originally Posted by zero
I find that even 2x the signal frequency is unreliable, e.g. I have a 24MHz USB LA but it can rarely decode USB packets and most USB peripherals use a 48MHz sample clock.
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Your sampling rate has to be much higher than whatever you're trying to measure, especially if your LA isn't synchronised with the source clock. A 24MHz sampling rate simply isn't enough to accurately capture a 12MHz signal. An absolute bare minimum would be about 1:4 just to be able to capture each transition, so you really need a minimum of 50MHz sample rate to deal with a 12MHz signal. DSLogic recommend a 1:10 ratio, so 120MHz sampling rate for a 12MHz signal.