[time-nuts] Interesting frequency standard project
alexpcs at ieee.org
Fri Jul 4 18:59:34 EDT 2014
for an AM station is strait forward at first use a narrow filter to make
sure that you have just one station and feed the filter out put into a
limiter the output of the limiter will be the carrier.
On 7/4/2014 3:27 PM, Hal Murray wrote:
> paulswedb at gmail.com said:
>> The key to these systems is that the transmitters have very good references.
>> In the US at least we have no requirement for that level of stability on the
>> MW broadcasts. Though evidently some stations are quite good. I think I have
>> a list some place have to re-look.
> How stable are they? Could they provide a good regional reference if
> somebody with a good setup would measure several stations and publish the
> results? How often would you have to measure?
> How do you measure the frequency of an AM or FM station? Wait for silence
> and process it like CW?
> Any suggestions for a receiver (or whatever) that would be appropriate for
> that sort of project? I assume the main requirements are an external freq in
> and a serial/USB port to adjust the knobs.
> Ages ago, I remember seeing a small booklet (20 pages?) from NBS describing
> their setup with HP that was using NBC's atomic clock for time distribution.
> HP's part was to run the west coast calibration to get the delay over phone
> lines from the east coast to the west coast. Has anybody seen a copy of that
> booklet online?
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