[time-nuts] WWVB format

Alexander Pummer alexpcs at ieee.org
Fri Nov 21 12:30:52 EST 2014

Hi Paul,
the phase modulation would interfere with the AM, since during the phase 
change the narrow band crystal filter's output will sink down as the 
filter is following the phase change, and the time needed for the filter 
to "swing in " to the new phase it depend on the angle of the phase 
change angle, for 180 degree it is 2 x [1/f] x Q  , [1/f] x Q needed to 
"swing on" and the same time to swing down from the old phase. 
[[Rohde&Schwarz's old Q meter is based on that, it counts the zero 
crossings until the level of the signal sinks to ....]]
and that causes an additional AM modulation, if the quartz filter of the 
clock  is not so good, the [1/f] x Q  time is shorter and the filter 
after the demodulator does not let it pass the amplitude change, thus 
the cheaper clock works better, until one switching mode power supply 
takes over the control from the WWVB....

On 11/21/2014 7:17 AM, paul swed wrote:
> Glenn
> I want to say that my simple wwvb clocks are working. However my most
> finicky one is not locked as I just noted. But then its always a problemed
> child.
> The format contains bpsk but that was not supposed to interfere with the
> traditional AM modulation these clocks detect.
> I might strongley believe that the various electronic lights that are
> becoming pervasive is seriously deteriorating the ability to detect the
> signal.
> I am near Boston so thats fringe.
> Regards
> Paul
> On Fri, Nov 21, 2014 at 12:06 AM, Glenn Little <glennmaillist at bellsouth.net>
> wrote:
>> Are there any "atomic" clocks that do not properly decode the current WWVB
>> format.
>> I have two that will not auto update the time and will troubleshoot if
>> this is not a format issue.
>> Thanks for any help.
>> 73
>> Glenn
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