On 07/20/2012 12:57 AM, Richard (Rick) Karlquist wrote:
A fast comparator seems like a good idea, and it is simple, however it is actually the last thing you want to use. High thermal sensitivity and high jitter.
Once your signal has past by a comparator, you can't "treat it" to remove the noise-induced jitter. As you gain the signal, the slew-rates can be made steeper and steeper prior to the comparator.
The benefit of a comparator is that if you add hysteresis, it stays in that position and does not cause transition spikes, which can cause false extra triggers, with resulting state-polution. You can see this on some counters when you trigger them on a slope with bad slew-rate... and the frequency goes unstably up. This is when the experienced trims the trigger point for lower jitter (better slew-rate).
Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
