From: Phil Hobbs
Subject: Re: What filer has equal ripple phase response, and where can I find the
pole positions for a 4th order filter?
Date: Mon, 20 Jan 2003 13:17:06 -0500
Organization: IBM T. J. Watson Research Center
NNTP-Posting-Date: 20 Jan 2003 18:17:11 GMT
X-Mailer: Mozilla 4.61 [en] (OS/2; U)
Jens Tingleff wrote:
> In article , "Peter says...
> >> Bessel filters have maximally-flat phase response, but what filter is a
> >> general case, with equi-ripple phase response.
> >> I'm asking because I would need to use an all pass network based on 6th
> >> Bessel poles (plus the 6 matching zeros of course) whereas I would hope I
> >> get by with 4th order if I relax the spec to equi-ripple phase (say +/-3
> >> degrees).
> >> Regards,
> >> Tony (remove "_" from email address to reply)
> Two references I like to quote. Involves different circuit structures, though.
> B J Bennet. A new filter synthesis technique the hourglass. IEEE Transactions
> CAS, 35(12):1469 1477, December 1988.
> D R Huard, J Andersen, and R G Hove. Linear phase analog filter de-sign with
> arbitrary stopband zeros. In Proceedings of the International Symposium on
> Circuits and Systems, pages 839 842, 1992.
There are tables for these in the Filter Bible:
Zverev, Anatol, "Handbook of Filter Synthesis", Wiley, New York, 1967.
An oldie but goodie.
This book contains zillions of tables of component values, and (IIRC) is
an excellent early example of a computer-typeset book--the values went
right from the generating program right into type without being redone