> Tom > > > The major source of interchannel phase shift instability will be the > phase shift instabilities of the sound card input RC coupling network > particularly if electrolytic capacitors are used and the input > frequencies are too close to the high pass RC filter 3dB frequency. > Amplifier phase shift instabilities are much smaller and the > interchannel group delay mismatch will be relatively small as the group > delay for each channel is determined by the digital filters used by the ADC. > > For temperatures around 20C a wet electrolytic cap has a tempco of aroun +500ppm/C or so. With a 0.5dBinput frequency of 20Hz a typical sound card has a high pass filter input time constant of about 33ms. At 1kHz the corresponding phase shift is about 800ns with a tempco of about 0.4ns/C.
Bruce _______________________________________________ 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.
