[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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