Electric Wave Filters

Many types of filters are used in practice,^4,5,7 but it is feasible to consider only the simplest structures. These will be composed of inductors and capacitors only, so that they may transmit freely over certain bands of frequencies. The assumption is made that the inductors and capacitors are lossless, and that no energy can be dissipated within the filter. The treatment will be confined largely to ladder-type structures, such as the equivalent T and π sections of Fig. 6.

Of great importance in filter design is the width of the transmitted band of frequencies. There are several ways of determining this, two of which will now be given.