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.
http://prc68.com/I/Loop.shtml#PhaseMod
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Alexander Pummer wrote:
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 modulation scheme?
73
Alex
On 9/23/2014 9:16 AM, Burt I. Weiner wrote:
Charles,
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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