Filter design by iterated analysis

An alternative to the classical synthesis of an LC ladder filter is to adjust the element values until some property of the filter, computed directly from the ladder, matches what is desired, and thereby confirms that the element values are correct. The paper describes a simple way of doing this by matching the poles, zeros, and scale factor of the characteristic function. The motivation behind this approach is to obtain high accuracy in the element values using a simple, noncritical computer program, at the expense of increased computing time. The accuracy achieved is higher than can be provided by synthesis techniques, and is illustrated by means of an example of a 15th degree elliptic-function filter.