ABSTRACT
The frequency response of a filter is usually measured by making a calculation on voltage measurements. Filters have one or more passbands, and one or more stopbands with substantial attenuation. An important application of a Norton transformation, in which an embarrassingly large series coil is reduced to a low value. Reactance transformations are used to transform a circuit so that its frequency response (phase, attenuation) will be transformed in a specified way. Any lowpass prototype can be transformed into a normalized highpass filter by reciprocation. Attenuation equalizers are RLC circuits that make relatively small adjustments to a given frequency response and are mostly used for correcting errors caused by parasitic components or other effects considered undesirable. By far the most important advantage of synthesis, however, is that it can give us designs having general parameter stopbands.
