[time-nuts] Making the most of SRS Rb source

Christopher Hoover ch at murgatroid.com
Wed Jan 18 23:31:44 EST 2006


This is an interesting discussion and aimed directly at my homebrew efforts.

> How about using the PRS10 in time stamping mode where you feed it
> the 1 PPS from the GPS and use a uC to read back the time stamp
> and the GPS saw tooth to get the actual delta time?  It would be
> easy to record these every hour and after a day or so make a
> tweak to the PRS10 frequency.  This way the only additional
> equipment would the the uC connecting to the PRS10 serial port.

That's an interesting idea.  I like it.

My goal is to put together a good GPSDO with isolated distribution. 

I'm currently have a PRS10, an M12+ timing receiver, a couple TAPR TADD-1's
tied together on my bench.  I aim to get it put into a single box with an
appropriate power supply and with some uC to drive a display and perhaps
USB.  I was going to use the uC simply to intialize and monitor the PRS10
and M12+, but after Poul's comments about the PRS10, I think I had better
re-think this plan.

Currently the first bits of the initialization and monitoring code are
together and running on a spare Linux box.

(Is this the sort of thing that others would like to collaborate on?  Some
help would be great.)

BTW, I asked Stanford Research last week about settings for the PRS10 with
1PPS driven from a GPS timing receiver.  The recommendation was stock
settings with a long integration constant, i.e, PT14.  I am currently
running this setting, but I haven't measured it yet ...

-- Christopher





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