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From: "Peter O. Brackett"
Subject: Re: New simple LC filter design program
Date: Thu, 26 Dec 2002 10:25:23 -0500
Organization: MindSpring Enterprises
X-Server-Date: 26 Dec 2002 15:25:21 GMT
X-Newsreader: Microsoft Outlook Express 5.00.2919.6600
"John Woodgate" wrote in message
> I read in sci.electronics.design that Peter O. Brackett
> wrote (in )
> about 'New simple LC filter design program', on Thu, 26 Dec 2002:
> >As a "teaser" the extremely simple formulae, known as Bennett's formulae,
> >for the "normalized" element
> >values of the N'th order Butterworth [a.k.a maximally flat] minimum
> >inductor, low-pass characteristic
> >function operating between one Ohm source and load resistances [R1 = R2 =
> >1.0 Ohms] with exact
> >unity passband ripple bandwidth and exact passband attenuation ripple
> >by Ap in dB are:
> >Ck = 2 eps^(1/N) sin(Pi (2k-1)/2N)): N - odd
> >Lk = 2 eps^(1/N) sin(Pi (2k-1)/2N)): N - even
> >Where: eps = sqrt(10^(Ap/10) - 1.0) is the passband ripple factor with
> >in dB.
> What is 'eps' for the Butterworth filters you say these equations apply
> to? It appears to be the square root of zero.
> Regards, John Woodgate, OOO - Own Opinions Only.
> Interested in professional sound reinforcement and distribution? Then go
> PLEASE do NOT copy news posts to me by E-MAIL!
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