[time-nuts] Lucent KS-24361, curious observation
hmurray at megapathdsl.net
Mon Dec 1 20:22:37 EST 2014
doug at dougronald.com said:
> 2) What is the 5 MHz crystal oscillator locked to? If it the L1 or L2
> carrier - cool, or the PRN code clock - okay, but if it is the 1 PPS - ugh.
> Since the sync signal must go through the jumper cable, I suspect it is the
> 1 PPS. Anyone know, and if it is the 1 PPS, is that as ugly as I believe?
All the GPS work is done in a small low-cost module, the type typical used in
consumer gear with a firmware tweak to work in position hold mode.
Generally, that gear is L1 only, and the only signals that come out of the
module are a serial port and the PPS signal.
Why do you think the PPS is "ugly"? It's generally derived from the crystal
that drives the CPU on the module. It's normally within 1/2 cycle (10s of
nano seconds) within the desired time. Some modules will tell you how far
off it is - the sawtooth correction.
These are my opinions. I hate spam.
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