Joseph M Gwinn wrote: > Bruce, > > > [EMAIL PROTECTED] wrote on 12/10/2008 04:46:50 PM: > > >> Joe >> >> Another limitation on using too low a beat frequency is imposed by the >> increasing equivalent input noise spectral density of the sound card as >> the frequency decreases. >> > > Yes, although people made good use of 1 Hz in DMTD instruments despite the > junk near DC. > > > Joe > Joe
The low frequency noise of the components used in their unoptimised slope amplifiers is significantly smaller than that of a sound card. A Collin's style optimised slope amplifier limiter may be useful for use with a sound card (particularly the lower resolution ones) if one is timetagging the beat frequency zero crossings. Less slope gain will be required than when driving a counter input. In the flicker noise region choice of beat frequency is relatively non critical. Bruce _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
