Greetings, I may be missing something here but when you receive a signal in the AM mode the audio is derived from the transmitted carrier. Even if your local osc moves around the audio is generated from the difference between the transmitted carrier and the audio sidebands.
I have found it quite convenient to calibrate a soundcard/SpecLab system using AM and the signals sent out by WWV at 500 and 600 Hz I think. Now if I could just get comfortable with SpecLab. Hi HI 73 Gordon WA4FJC ---------------------------------------------------------------------- Message: 1 Date: Tue, 12 Oct 2010 17:03:26 -0700 From: David McClain <[email protected]> Subject: Re: [time-nuts] Question about SoundCard stability? To: Discussion of precise time and frequency measurement <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > Best guess is that the codec in the Flex runs on the same TCXO as > the rest of the radio. That's my best guess too... so how is it that I'm seeing 25x less variation in the audio signal than the TCXO is capable of yielding? I have the central air conditioner cycling on and off all day (Tucson desert), and I can see the radio wander by as much as +/-2-4 Hz at times, at 10 MHz. It shows an irregular sawtooth deviation in sync with the cycling of the air conditioner, with a period of about 45 minutes, 15 of which are cool down times. This is mid-day, so the ionosphere is not producing much in the way of Doppler shifting. And even if it were, that shouldn't be measurable to me at the audio frequencies. Dr. David McClain Chief Technical Officer Refined Audiometrics Laboratory 4391 N. Camino Ferreo Tucson, AZ 85750 email: [email protected] phone: 1.520.390.3995 web: http://refined-audiometrics.com _______________________________________________ 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.
