Boy Chris I don't know what to say here I use IRIG B decoder displays and they have been happy with my free running xtal oscillator for 12 years. I do not recall IRIG B making phase lock a requirement. I use gps to get a time stream then a SXB micro to convert that to IRIG B... Regards Paul. WB8TSL
On Tue, May 14, 2013 at 1:35 PM, Chris Albertson <[email protected]>wrote: > OK the 555 timer is not so good of an idea. You need a phase locked > 1KHz oscillator. > > You can also buy IRIG cards for the PCI bus. We used them where I > used to work. They are not cheap. Almost any company that working in > timing or telemetry will have these cards. > > But still if the goal is to have the computer's system time track > irig, use NTP. It should be easy to build a phase locked 1KHz > oscillator. 1K is such a low frequency. I'd thing a 4046 chip would > do the job. > > On Tue, May 14, 2013 at 10:04 AM, Esa Heikkinen <[email protected]> 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 > > complex... > > > > Does anyone know if the soundcard based IRIG decoder will follow the > phase > > also, or only the amplitude (?) > > > > -- > > 73s! > > Esa > > OH4KJU > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
