[time-nuts] 1 pps Sync'ing
Hal Murray
hmurray at megapathdsl.net
Sun Jun 24 20:47:31 UTC 2018
> I need the rising edges of both the 10 MHz and 100 MHz squarewave outputs to
> be aligned with the GPS 1 pps (UTC) to within 1 ns.
That will be interesting. You may have to get your cables and distribution
amplifier inside the PLL.
How good is your GPS? What's the night/day difference in GPS timing? (after
sawtooth correction)
What is your application? What sort of noise/jitter/wander are you sensitive
to and/or what can you tolerate?
One thing you can do is to derive the 10 MHz from the 100 MHz with a simple
divide by 10. Then run both through reclocking FFs. If they are in the same
package with the same clock, they will be closely aligned, but there will be
"noise" from the 10MHz on the 100 MHz due to different loads on the power
supply wiring. That's probably sub ns.
Do you need your PPS to be aligned to UTC? If not, divide down to make your
own PPS and run it through the same reclocking.
If you do need your PPS aligned to UTC, you can PLL your PPS with the PPS from
GPS. The S part of PPS means that things are slow so a software/DAC solution
will probably be appropriate.
--
These are my opinions. I hate spam.
More information about the Time-nuts_lists.febo.com
mailing list