[time-nuts] Is there any IRIG-B hardware decoders available?
paulswedb at gmail.com
Tue May 14 13:43:14 EDT 2013
I pretty much doubt the SB ever went to the phase level. Really no need for
that the average offset and detection point on the AM signal was good
enough. I have done what was suggested just modulate a 1Khz signal though I
did use an xtal oscillator. It worked fine.
On Tue, May 14, 2013 at 1:04 PM, Esa Heikkinen <tn1ajb at nic.fi> wrote:
> Chris Albertson kirjoitti:
> NTP will so this. There is an IRIG reference clock. You really do
>> want to use NTP to discipline the PC's clock. Almost every other
>> method is worse and causes time discontinuities.
>> If you happen to have TTL level IRIG it s very easy to convert it to
>> amplitude modulated IRIG. The standard is a 1KHz tone.
>> Build a cheap 1KHz oscillator. A 555 timer is good enough. Then you
>> a single transister if IC time switch to modulate the amplitude of the
>> signal. The details are not critical.
> That's good idea if the phase of the 1 kHz signal is not critical?
> I checked the IRIG-B signal with oscilloscope and looks like the 1 kHz
> signal's phase is locked to the time signal. The bits will always start and
> stop at exactly same phase. That makes sense because with phase detector it
> could be possible to get very accurate timing from the 1 kHz signal - much
> better than following the amplitude only. That's one reason why I was
> interested about chipsets; if they can follow the phase also. I think if I
> design any hardware for that it should follow the phase also? It may be
> Does anyone know if the soundcard based IRIG decoder will follow the phase
> also, or only the amplitude (?)
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