3. Simplified LC filter synthesis principle

In practice, the vast majority of LC filters have a ladder structure. This topology avoids the use of transformers and has proved to give the best results.

Starting from a given template, we need to determine the schematic and calculate the value of the elements in this schematic.

Cauer and Darlington developed a systematic method for synthesizing ladder filters from the transfer function and the characteristic function. This very powerful method is based on a very complex theoretical development, yet its implementation is very straightforward, provided we restrict ourselves to classical ladder structures. This simplified procedure is suitable for the vast majority of filtering applications in acquisition systems. This simplified method involves first calculating a prototype low-pass filter with a simple, repetitive structure (canonical...