Filtering device for processing a plurality of channels in a cable television distribution system

摘要

The filter includes a number of slave filters (1-8) which are in parallel and process individually a number of channels in the system. Each filter has a frequency response which is individually voltage controlled. For each slave filter, there is a corresponding master filter (11-18) with an identical filtering cell. Signal separation of incoming signals is achieved by use of frequency synthesisers (21-28). Each synthesiser has a phase-locked loop which applies a feedback voltage to a master cell and slave cell circuit at the same time. Each master/slave filter is realised on the same semiconductor IC.