Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/3/84; site teddy.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!teddy!rdp From: rdp@teddy.UUCP Newsgroups: net.audio Subject: Re: David Mohler is completely correct Message-ID: <1167@teddy.UUCP> Date: Tue, 20-Aug-85 10:00:51 EDT Article-I.D.: teddy.1167 Posted: Tue Aug 20 10:00:51 1985 Date-Received: Fri, 23-Aug-85 05:24:48 EDT References: <19@drune.UUCP> <4162@alice.UUCP> <4164@alice.UUCP> Reply-To: rdp@teddy.UUCP (Richard D. Pierce) Organization: GenRad, Inc., Concord, Mass. Lines: 21 In article <4164@alice.UUCP> jj@alice.UUCP writes: > >Just as an aside, I'm interested in those filters that >Mohler has invented that have no ringing. It's odd, >but I've written a few papers on filter design, a few more >on audio, etc, and all of the filters I've seen worked because >they had "ringing". Funny thing, a filter with no ringing >passes just perfectly well as NO FILTER. > >Check out Rabiner and Gold, Oppenheim and Schaeffer, or any >other basic text. > Correct me if I am wrong (and I am sure the righteous amongst certainly will, in a most vehement manner), but do not filters of the Bessel persuation (or some other forms of constant time delay) succeed in filtering without ringing? Also, I have yet to see any evidence of a first-order filter even having overshoot, much less ringing, or is something wrong with my scopes, resistors, capacitors and books?