[time-nuts] SA22.c and Lady Heather
dave.mallery at gmail.com
Sat Sep 2 17:48:38 EDT 2017
on the 2011 or newer items, they include this link calibration data plot.
i received a printed one with the unit.
On Sat, Sep 2, 2017 at 6:55 AM, Mark Sims <holrum at hotmail.com> wrote:
> The data that RDR showed was from the SA22.c "w" command. I think he was
> just using a terminal program.
> Attached is a screen dump of Heather doing a software disciplining
> algorithm on a SA22.c (using the dev board as an interface). The 1PPS
> reference that I am using is the nosiest one that I had handy (LEA 5T,
> indoor antenna, second 1PPS output... it has over +/- 66 ns of jitter).
> Heather can also calibrate the SA22 / X72 frequency output. You apply a
> 1PPS input, enter &a and a sample count (default 1800 seconds). It then
> calculates the drift rate from a linear regression trend line and sets the
> device DDS tuning word. The resolution of the DDS in the device is around
> 2.5E-12 / count.
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Dave Mallery, K5EN (ubuntu linux 16-10)
PO Box 15 Ophir, OR 97464
linux counter #64628 (since 1997)
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