[time-nuts] A new take on the all-hardware GPSDO concept
davidwhess at gmail.com
Tue Sep 27 01:02:45 EDT 2016
Is there a schematic showing what you attempted?
I went back through the discussion thread and it was not real clear to
me which design you implemented.
On Mon, 26 Sep 2016 21:18:25 -0700, you wrote:
>The results arent very good.
>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, its locking significantly off frequency.
>Thats 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 Ive 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 doesnt work at all.
>But the real nail in the coffin here is that the price of the PLL chip is still more expensive than the microcontroller and all of the components it replaces.
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