Application of Bandpass Filters to Color TV IF Amplifiers

Of the numerous functions required of the IF amplifier in a modern television receiver, selectivity is undoubtedly the most difficult to achieve. Operating parameters such as gain, stability, linearity, signal-handling ability, voltage output and gain-reduction capability are achieved by rather straightforward means of design. Selectivity requirements are severe, calling for placement of several specific frequencies with close tolerance within the passband of the amplifier while simultaneously attempting to reject frequencies extremely close to the edges of the desired passband. In color television receivers, the problem is especially compounded because results depend on maintenance of low phase distortion between the 6 dB points of the response curve. The new bandpass-filter IF amplifier efficiently handles these problems and helps produce a high quality picture even from a low quality signal.