Resampling methods

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4 total messages Started by Bill Dorsey Sun, 10 Jan 1993 20:22

#2201

Author: Bill Dorsey
Date: Sun, 10 Jan 1993 20:22

14 lines
1024 bytes

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)?

The only reference to resampling I can find in my DSP book involves
taking a DFT of the input signal, truncating or padding it as appropriate,
and then taking it's inverse.

-- 
Bill Dorsey      "Most people mistake law for justice and authority for
dorsey@lila.com   liberty.  You will hear them talk of 'liberty under law,'
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Re: Resampling methods

#2209

Author: Jeff Warner
Date: Mon, 11 Jan 1993 14:10

37 lines
2073 bytes

    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

Re: Resampling methods

#2208

Author: John W. Herman
Date: Mon, 11 Jan 1993 21:19

7 lines
690 bytes

koffie@muresh.et.tudelft.nl (Andre Nieuwland) writes:


> In article <C0nn9C.o5@lila.com> dorsey@lila.com (Bill Dorsey) writes:
*** Stuff deleted ***
>You can also try to find some papers on interpolating filters.
Or multirate digital signal processing.

Re: Resampling methods

#2206

Author: Andre Nieuwland
Date: Mon, 11 Jan 1993 23:03

28 lines
1658 bytes

 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

You can also try to find some papers on interpolating filters.

Good Luck,

Andre Nieuwland

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