Will, For long-term tracking 60 Hz (or any audio timing signal) with a sound card you don't need a high quality.
Either use the PC to timestamp receive buffers, or if you have a 1pps handy, just feed your 60 Hz signal into one channel (L) and the 1 PPS into the other (R). Either way drift in the sound card oscillator is irrelevant. With little effort you can track the 1PPS to within 1 sample (about 10 us at 96 kHz), which is way more precise than the average 60 Hz power cycle. Essentially what you're doing then is using 1 PPS as your long-term accurate reference and using the sound card merely as a cycle counter. For this the cheapest possible sound card will do the job. As described a day or two ago even a clockless one bit "sound card" works at 60 Hz., i.e., a serial port DCD pin. So in spite of the allure of using a sound card, it seems a serial port is even a simpler solution if all you want to do is count and time cycles. /tvb _______________________________________________ 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.
