[time-nuts] A new take on the all-hardware GPSDO concept

Bill Hawkins bill.iaxs at pobox.com
Tue Sep 27 09:18:18 EDT 2016

What kind of capacitor is used for the 10 µF cap - electrolytic or film?

Bill Hawkins 

-----Original Message-----
From: Nick Sayer via time-nuts
Sent: Monday, September 26, 2016 11:18 PM

With a short TC loop filter, the PLL does lock up, but obviously the
jitter of the Venus’ 10 MHz output comes through.

With a longer TC, the PLL never locks - or at least if it does lock,
it’s locking significantly off frequency.

That’s with a 10 µF cap and varied resistors between 10k and 1M. The
best I got was at 200k - a TC of 2s. That resulted in this video. Unlike
other videos I’ve made comparing two GPSDOs, this one is not a
time-lapse. The reference is an OH300 based GPSDO.


A time constant of 10s (1M resistor) just doesn’t work at all.

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