[time-nuts] WWVB BPSK Receiver Project?

Attila Kinali attila at kinali.ch
Thu Mar 15 16:05:29 UTC 2012


On Thu, 15 Mar 2012 07:49:15 -0700 (PDT)
"J. Forster" <jfor at quikus.com> wrote:

> Suppose the modulation is not present. The output of the phase detector
> that steers the local standard ot indicator works correctly.
> 
> Now reverse the 60 kHz carrier. The phase detector works exactly thye
> opposite way...  wrong.
> 
> Now alternate between 0 and 190 degrees.
> 
> The loop alternate works between exactly right and exactly wrong...  it
> dithers around and the output is a measure of the ratio of 1's to 0's and
> is utterly useless.

That under the assumption, that they do not make sure that the average
phase is zeros out (or converges to 90°). I have not found anything
taht suggests this... on the other hand, there is nothing that suggests
the contrary either.

But you didnt address my main point yet: The phase of the WWVB signal
is already fluctuating a lot, just by natural occuring atmospherical
"noise". If a 180° phase shift does destabilize your PLL, what does
these "shifts" which are much larger do?

			Attila Kinali

-- 
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin




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