Patches

[Eli Brandt]

jbv wrote:
[a bunch of discussion snipped]
> * at first, it seems that CV signals and audio signals must be considered
> from different points of view : 100 or 200 Hz looks like an acceptable
> sampling frequency for CV signals (keyboard CV, ADSR, etc.), but audio
> ins/outs (when used as control signals) require a much faster sampling
> frequency (44.1 KHz actually) [...]

Don't lock yourself into too low a sampling rate for your control signals.
What I've seen in the digital domain is that if you don't interpolate CVs,
you really can't get away with much subsampling.  Look at a 5-ms linear
attack: it's moving at 200 V/sec, so stepped sampling at X Hz introduces
error in the form of AM by a sawtooth of 100/X p-p, meaning sidebands
starting at (20 - log X) dB.  If X is 1 kHz, that's only 10 dB down.
(Actually, this sounds too high, but my point remains the same. :-)
Linear interpolation introduces 1/X seconds of latency, but it lets
you use sub-audio-rate signals without nearly as much digital crud.

-- 
   Eli Brandt
   eli+ at cs.cmu.edu