Partial-Fraction Expansion?
 

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?

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Partial-Fraction Expansion?
 

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?

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.


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

--


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Partial-Fraction Expansion?
 

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


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net