[time-nuts] WWVB remodulator for the Spectracom 8170...

[Bob Camp]

Hi

I suspect it will be a while before we see a phase locking / phase comparing receiver chip that works with the new modulation. I'd bet on them simply putting out the demodulated data. Since that chip just tells me what time it is, I don't see a lot of benefit in having one.

Even if I can't demodulate *all* the bits, I can demodulate most of the bits. I know which slots are which. A good job of phase comparison can be done with just the recoverable bits. I'd still rather see a definition of the format that's not marked "preliminary" before moving down that road. 

Bob

On Jun 17, 2013, at 6:03 PM, Chris Albertson <albertson.chris at gmail.com> wrote:

> Yes the simple "re-modulator" fixes the time of day display but leaves the
> frequency output about as good as the tuning fork crystal.
> 
> I think the ONLY way to make it work 100% like new is to build a new
> receier that actually decodes the phase inversions and "knows" when the
> carier phase is flipped.   Thenit can "un-flip" the carrier.    There is no
> way to predict some of the bits, you just have to detect it in real time.
> You can verify the scheme is correct because the counter will increment
> each second.  So the radio can know which phase is up and which is down.
> 
> Until they sell one-chip WWVB chips using the new encoding it may not be
> worth in except for those who don't trust GPS and want WWV as a backup.
> 
> 
> On Mon, Jun 17, 2013 at 2:08 PM, Charles P. Steinmetz <
> charles_steinmetz at lavabit.com> wrote:
> 
>> Burt wrote:
>> 
>> In a sense you could say that Paul's circuit does get the WWVB signal to
>>> the receiver - it's just a new phase stable version of the signal signal.
>>> This way I don't have to mess with the insides of the 8170.
>>> 
>> 
>> Note that the 1 MHz TTL signal on the rear panel of the 8170 will not be
>> phase locked to the WWVB carrier -- it will be phase-locked to the 60 kHz
>> carrier supplied by the re-modulator's crystal oscillator.
>> 
>> One might try to injection-lock the re-modulator's crystal oscillator to
>> the WWVB carrier, but presumably the PSK would work against you here.
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
>> 
>> 
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> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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