Hi

It is a very very long time since I have done this, but...
You can pitch shift a digitised signal using a variation on
interpolation. You essentialy resample the signal on the fly,
generating more or less samples, as required before shifting them out
the back end of the system (D to A perhaps?).
This is a very old method and there is probably a better way of doing
it now, perhaps using a DSP, and an FFT or DCT based algorithm?

Sorry to be so vague, hope this helps a bit.

Jason

> > As part of a PIC project (naturally), I am looking for a method
> > of shifting
> > audio frequencies (100 Hz - 3.1 KHz) down 10% or so.  Can anyone point me
> > in the proper direction?  My background is all digital but I'm able to
> > learn  ;-)
> >
> > Jim
> > jdolson@iserv.net
______________________________________________________________________

A conclusion is simply the point where you got tired of thinking.


Phone +44 (0)161 275 4094

Jason.Bent@man.ac.uk

I am a technician in the Dept. of Physics & Astronomy
at Manchester University