[time-nuts] WWVB d-psk-r down conversion method...
alexpcs at ieee.org
Tue Sep 23 13:11:08 EDT 2014
there is an interesting side effect with that phase modulation: in case
the crystal filter is "narrow enough" --to use for the old AM format--
the phase change creates an additional AM modulation, if you take in
consideration that effect by the decoding the modulation, you could
recover the time information "despite" of the presence of the PSK.....
Question: as fare as I am informed there is no chip/system available to
correctly decode the new signal form, what was the purpose of the whole
modulation format change?
The old AM format was happy with cca 200Hz bandwidth to recover the time
information, which was utilized in many professional receivers, which
used a crystal filter for 60kHz, for the PSK format the required
bandwidth is at least five times wider, so crystal filter would be
problematic and much more costly, the higher required bandwidth brings
also more noise ....actually where is the advantage of the new
On 9/23/2014 9:16 AM, Burt I. Weiner wrote:
> If I recall correctly, the original point of the d-psk-r was to cause
> the clocks to again read the correct time, not maintain their use as a
> frequency standard. I have a Symmetricom 8170 that I used to use only
> as a clock to tell the time of day. Since WWVB's addition of the PSK
> coding, it's only good to watch the pretty blinken lights.
> Burt, K6OQK
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