🚀 go-pugleaf

    In article <C0nn9C.o5@lila.com> dorsey@lila.com (Bill Dorsey) writes:
       I have a signal which is sampled at F1 hertz which I want to resample
       at F2 hertz.  Neither F1 nor F2 divide each other evenly.  Are there
       any methods which can be used to resample F1 directly (e.g. not first
       transform it into some other domain)?


   You might try using Interpolating FIR filters.
   Basically you stuff zero's between the time samples you already have, and thus
   converting your sample rate to F1*F2, (if possible divided by the Greatest
   Common Divisor of f1 and f2) filter this signal with the Interpolating FIR
   filter, and then decimate the sample rate with another FIR-filter to obtain
   a rate at F2.
   Note that the interpolating filter runs at the higher speed F1*F2/GCD(f1,f2)
   and the decimation filter at the speed F2.

   There is some info in:
	   Digital Signal Processing
	   From Roberts, Clifford and Mullis
	   Addison Wesley Publishing Company
	   page 447-449

   Good Luck,

   Andre Nieuwland

It is not necessary to run the any filter at f1*f2 rate, see the
following reference from the FAQ.  Half of your device runs at f1, the
other at f2, with a double buffer in between.

R. E. Crochiere & L. R. Rabiner, "Multirate Digital Signal Processing",
Prentice-Hall, 1983, ISBN 0136051626.
This book is the only real reference for filter banks and multirate
systems, as opposed to being a tutorial.


Jeff Warner