[time-nuts] pps vs. 10 MHz timing
boyscout at gmail.com
Fri Dec 12 02:42:58 UTC 2008
On my Oscilloquartz GPSDO, the 10 MHz output goes low at very close to
the same time as the 1 PPS output goes high.
On my Fury, the 10 MHz sine wave is just dropping off of its max high
voltage as the 1 PPS goes high. The 10 MHz CMOS output goes high just
shortly before the 1 PPS.
What do other GPSDOs do?
Clearly, any device trying to latch the 1 PPS signal using the 10 MHz
clock will need to choose which clock edge to use, depending on which
type of GPSDO is used. How is this normally handled?
Also, I noticed that the TADD-1 has some weird distortion of a 10 MHz
sine wave. It turns it into a sort of a 3 valued square wave.
Essentially, it stops and dwells at the midpoint for a while instead
of making a sharp transition. I think this would be bad if that dwell
point is close to the threshold for the receiving device. Has anyone
else noticed this?
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