Audio demodulator for multireceiver PAL television system

摘要

The demodulator includes an antenna (20) which receives television signals from a broadcast station. An intermediate frequency signal is generated. A first oscillator (24) generates three signals at frequencies applicable to different broadcast standards. The intermediate frequency signal is input to a first mixer (23) with one of the signals produced by the first oscillator and the output is filtered (25). A second oscillator (27) generates a fourth frequency signal in order to convert the filtered intermediate frequency signal using a second mixer (26). A low frequency second intermediate frequency signal is produced and input to a passband filter (28) and amplifier (29), then passed to an FM detector (30) to produce an audio output.