[time-nuts] Correcting jitter on the 1 PPSsignalfromaGPSreceiver.
magnus at rubidium.dyndns.org
Sat Sep 20 07:47:02 EDT 2014
It's the rise-time that kills you.
You can under certain circumstances avoid termination, and gain better
amplitude, but you then need to make sure that the reflections is not
going to disturb your measurements.
The general recommendation is to do proper termination. If you know the
signal and reflections, you can play it differently.
Remember, the sharper rise-time, the more high-resolution ringings you
wake up. Sometimes you get better signal integrity simply by reducing
the rise-time, as there is less energy to confuse you.
In the end, this is a topic one can go deeply into. There are many quirks.
On 09/15/2014 03:43 PM, Tom Van Baak wrote:
> How important are all these cable / termination / impedance issues for 1PPS signals? I know ringing and reflections are undesirable in many applications. But for 1PPS?
> I often use pick whatever cable, termination, and trigger level gives the cleanest edge, the best risetime. What happens to the signal tens or hundreds of nanoseconds after the edge seems irrelevant to me. Could one of you RF experts comment?
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