Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
Subject: Re: New simple LC filter design program
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Thu, 26 Dec 2002 08:06:28 -0000
NNTP-Posting-Date: Thu, 26 Dec 2002 08:06:31 GMT
Peter O. Brackett wrote:
> Thanks for another great program!
> However, as usual we are not privy to your methods of calcualtion. I
> was wondering???
> Does your program use the simple, venerable, but approximate, image
> parameter design formulae?
I doubt if anyone would use this method. Its very old, inherently a
false method, with quite a lot of misc programs about that use the
> If not then perhaps you are aware of, and have been delighted by, the
> remarkably simple explicit
> formulae for the exact element values of low-pass, all-pole, ladder
> filters with Butterworth and
> Chebychev characteristic functions. These remarkably simple formulae
> involve only the trigonometric
> functions powers and square roots, and may be executed easily by
> hand on a scientific calculator.
I would be interested in the explicit Chebychev LC solution. Could you
Despite this, my SuperSpice program calculates Chebychev LP and HP for
orders up to 17th, for fixed ripples of 0.01, 0.1, 0.5, 1, 3 db for LC
formats, and any order and ripple for op-amp versions. It already uses
the explicit Butterworh LC ladder formulas. in additon you can
autmatically place the circuit on the schematic, and run a normal spice
simulation on the filter. This xan vbe done with the demo version
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.