[time-nuts] WWVB d-psk-r down conversion method...
brooke at pacific.net
Tue Sep 23 18:11:23 EDT 2014
There's not a requirement that Xtgendwave make the chip. The modulation format is published by NIST and anyone can make
I would hope there's some Time Nuts that would be interested in doing this rather than trying to remove the phase
It's my understanding that by using the fast (100 bits/second - 10 second frame time) signal you can get more precision
than possible using the old WWVB signal.
Note: The Xtgendwave patents spend a lot of time and effort compensating for the poor quality of the watch crystal. If
it's in spec but not exactly on frequency, then decoding a signal that's 17 minutes long is a big problem. For time
nuts use where we have a precision LO all that goes away and instead we could be looking at how to get more precision
and at the same time more updates.
Alexander Pummer wrote:
> Hi Brooke,
> I hope that you are right with that chip, and despite the name change of the company -- now Xtendwave -- and
> recovering they will deliver something some times. I can see that with correlation and averaging schemes the signal
> to noise ratio of data, perhaps constant frequency could be improved, but I would be very interested to see of the
> mathematical model of improving the signal to noise ratio of timing.
> On 9/23/2014 1:08 PM, Brooke Clarke wrote:
>> Hi Alex:
>> Sometime in the future there will be chips that will decode the new signals (note the "s" on the end of that last
>> word). There are a number of frame times the longest one of which takes 17 minutes and is transmitted only once per
>> day. This format offers 23 dB modulation gain compared to the 1 minute time frame transmission that the current
>> clocks use. There are a total of 5 different modulation formats that will be transmitted over different time
>> frames. In the end everyone should have a clock with more frequent updates (on the West coast I might need to wait
>> overnight for a clock to sync after a battery change) and more accuracy.
>> Have Fun,
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