[comp.sys.ibm.pc.misc] Digital filtering

ao@lne.kth.se (Anders Ohlsson (Royal Institute of Technology, Stockholm, Sweden)) (09/05/90)

	Can anyone help me with an algorithm for filtering speech
	files that are sampled at 8 kHz. I am going to downsample
	them to 6 kHz, and need to have a 3rd order LP-filter at
	2.8 kHz.

	I'd greatly appreciate if someone could point me to a
	program that does this. If it's available, I'd like a
	general program for LP-filters, HP-filters, bandpass
	and bandstop-filters (nth-order).

	Any algorithm or program for calculating the filter
	parameters would appreciated.


				Thanks in advance,

					Anders Ohlsson

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| In real life: Anders Ohlsson               E-mail: ao@lne.kth.se |
|                                                    ao@infovox.se |
|                                                                  |
| "Complex problems have simple, easy-to-understand wrong answers" |
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north@manta.NOSC.MIL (Mark H. North) (09/06/90)

In article <0093C415.AB8D7C00@lne.kth.se> ao@lne.kth.se (Anders Ohlsson (Royal Institute of Technology, Stockholm, Sweden)) writes:
>
>	Can anyone help me with an algorithm for filtering speech
>	Any algorithm or program for calculating the filter
>	parameters would appreciated.
>

An excellent book in this regard is Stearns, S.D., "Digital Signal Analysis", Hayden Book C. 1975. Unfortunately it is out of print but your library may have
it.

Mark

grosen@amadeus.ucsb.edu (Mark D. Grosen) (09/06/90)

In article <1199@manta.NOSC.MIL> north@manta.nosc.mil.UUCP (Mark H. North) writes:
>In article <0093C415.AB8D7C00@lne.kth.se> ao@lne.kth.se (Anders Ohlsson (Royal Institute of Technology, Stockholm, Sweden)) writes:
>>
>>	Can anyone help me with an algorithm for filtering speech
>>	Any algorithm or program for calculating the filter
>>	parameters would appreciated.
>>
>
>An excellent book in this regard is Stearns, S.D., "Digital Signal Analysis", Hayden Book C. 1975. Unfortunately it is out of print but your library may have
>it.
>
>Mark

There is a second edition out of this book:
	"Digital Signal Analysis"
	S. D. Stearns and D. R. Hush
	Prentice Hall 1990
	ISBN 0-13-213117-X

It comes with a DOS floppy with Fortran source code and includes some simple
design routines.

You might also check out "Digital Filters" by Tom Parks (sorry, I don't
have the book here).  This is a comprehensive look at designing filters
and includes Fortran code (but no disk).

There are several commercial SW packages available, but they are rather
expensive.

Mark


Mark D. Grosen		ARPA: grosen@amadeus.ucsb.edu
Signal Processing Lab / Communications Research Lab
ECE Dept.
University of California
Santa Barbara, CA  93106