On 01/27/2015 07:15 PM, bitrex wrote:
Jim Thompson
Wrote in message:
Someone please refresh my memory...

Isn't there some easy way to do a "partial-fraction expansion" of a
transfer function in "S" (Heaviside version of Laplace) and generate
an L-R-C ladder network?


I don't know that there's any easy way to do it by hand, no.
That's why for the "standard" filter types, someone went to the
trouble of computing "normalized" filter tables for ladder
networks.

With something like SciPy or Matlab, if you have a candidate
filter topology and the transfer function of your filter it
should be possible to write a program that can find the transfer
function of the network and solve for the component
values


A partial-fraction expansion will give you a sum of quadratic terms,
each of which will look like a parallel LRC section. That leads
directly to a realization: buffer the tank voltage and sum the results.
Getting the ladder realization is tougher, as others have noted.

Cheers

Phil Hobbs


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Dr Philip C D Hobbs
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