[time-nuts] Heathkit GC-1000 WWVDO
John Ackermann N8UR
jra at febo.com
Thu Mar 1 19:53:33 UTC 2012
On Mar 1, 2012, at 11:41 AM, Brooke Clarke <brooke at pacific.net> wrote:
>Are there any WWVB disciplined oscillators (WWVBDO)?
I have a couple of Spectracom 8164 WWVB DOs running. They bounce around by a part or three in 10e10.
The 8164 uses an FLL that does 1000 second counts of the internal OCXO reference vs. a 10 MHz crystal that is tightly locked to the WWVB carrier. An algorithm adjusts a DAC based on the counter results, after applying sanity checks (e.g., I think it requires two or three consecutive counts within some tolerance before it makes an adjustment).
John
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