On Mar 16, 2012, at 1:32 AM, Peter Monta wrote:
> Attached are some more renderings of John Seamons' WWVB data. This is
> what one might expect from a receiver that knows when the phase
> reversals happen and takes them out noiselessly---re-reversing the
> out-of-phase bursts to recover an approximation of the usual WWVB
> signal.
Thanks for the additional analysis Peter. Odd that there is significant phase
jitter.
I've added to my website the only other significant recording I made: ten
minutes in the dead of night (2:27 AM MST, 9:27 UT).
http://www.jks.com/wwvb/wwvb.html#10-min
The phase data I extracted is the same as the two minutes of data I captured
earlier. A constant pattern that repeats every minute. Certainly not the full
protocol as described in the NIST paper. So maybe this test was to simply
evaluate the phase modulation effects on receiving equipment (in which case
it's shame we didn't find out earlier so we could do more boat-anchor
compatibility testing).
In an earlier message Dennis Ferguson points out that the paper doesn't fully
specify the 11/14-bit minute-sync and 60-bit hour-sync codes. So it's not clear
what they were actually transmitting. They do talk about using the 11-bit
Barker code for autocorrelation. But the sync bits transmitted only match the
Barker code if you interpret them a little bit out-of-order.
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