[time-nuts] Measuring gpsdo vs itself
Hal Murray
hmurray at megapathdsl.net
Mon Nov 5 05:06:18 UTC 2012
docdailey at gmail.com said:
> I guess what I am saying is if I discipline the counter with 10MHz and then
> measure the same 10MHz. Just making sure we are on the same page.
The input signal will be at a fixed offset from the reference clock. That
offset will depend on cable lengths.
If that setup gives a bad result, you know something doesn't work well. If
it gives a good result, I don't think you can assume it will work well with
other input signals.
You might try using the GPSDO as the reference and measuring a typical
crystal oscillator package. They are usually quite stable short term. Long
term they track temperature.
Beware, some low cost oscillator packages have internal DDS. Check the specs
for jitter. [I think the idea is to ship unprogrammed packages to
distributors where they can be programmed to order and shipped with low
turn-around-time.]
--
These are my opinions. I hate spam.
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