[sdiy] Dumb PWM question

[jbv]

Tom Wiltshire a *crit :

> I've done this with digital oscillator waveforms (generalised phase
> distortion, of which PWM is a special case), but I can't see how
> you'd do it without sampling, since it is effectively a time
> distortion, and that's going to require some stored waveform.
> I suppose the sampling could be done in the analogue domain (magnetic
> tape?) with the PWM applied as a modulation to tape speed at the
> input frequency.
> It'd be a LOT easier on a DSP though....

that's exactly what I thought... actually it's time compression for 1 half
of
the period and time expansion for the other half...

JB