[time-nuts] Comparing PPS from 2 GPS units
lists at lazygranch.com
lists at lazygranch.com
Thu Dec 13 10:25:12 UTC 2012
They make frequency difference meters. I never used one, but it seems to me a frequency difference meter would just use the two input signals to toggle up and down respectively on a counter, then display the result over a fixed period.
Would this do what you want?
------Original Message------
From: Hal Murray
Sender: time-nuts-bounces at febo.com
To: time-nuts at febo.com
ReplyTo: Discussion of precise time and frequency measurement
Subject: [time-nuts] Comparing PPS from 2 GPS units
Sent: Dec 13, 2012 1:57 AM
Suppose I want to compare the PPS outputs of 2 GPS units. The problem is
that I don't know which one will happen first.
If I feed them into the start/stop inputs of a typical timer/freq box, I
don't know which is which. If I get them wrong, the answer will be
0.999999xx seconds rather than the -0.000000xx that I want.
Is there a simple solution for this?
My straw man is to use the antenna cable delay setting to offset one of the
PPS pulses a long way.
Plan B would be a physical delay unit. But they are probably temperature
sensitive, and I'm not setup to keep anything at a constant temperature.
Do any of the counter/timer boxes have a mode for this? If so, is there a
buzzword I've overlooked?
--
These are my opinions. I hate spam.
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
More information about the time-nuts
mailing list