LOW-PASS STEP ATTENUATOR

摘要

A filter circuit is constructed as a triplex filter having a high-pass filter, a low-pass filter with attenuation in the passband, and a second low-pass filter without attenuation in the passband. The filter circuit has a frequency response with a high-pass portion, a flat loss portion, and a low-pass portion. Attenuation in the flat loss portion is uniform and is predetermined via selection of filter components. The filter circuit is useful in a bidirectional CATV system in which performance is improved by selectable attenuation of a first source of return path signals but without attenuation of a second source of return path signals.