[time-nuts] pps vs. 10 MHz timing

[Matt Ettus]

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?


Thanks,
Matt