SOUND MULTIPLEX DEMODULATION CIRCUIT OF 12/NICAM COMMON USING

摘要

The demodulator is incorporated in a television or a video cassette recorder for receiving both an A2 broadcast and a NICAM broadcast available in PAL B and G broadcast regions in Europe. The circuit comprises a video signal processor 40; a main channel audio signal processor 50; a sub-channel audio signal extractor 60; an A2 broadcast processor 70; a NICAM broadcast processor 80; a matrix circuit 23; a selector means 31; a first cut-off switch SW1 coupled to output terminals of said matrix circuit; a second cut-off switch SW2 coupled to output terminals of said selector means; and a display 32. The extractor 60 shifts the frequency of one of the audio sub-channels of A2 or NICAM broadcasts so that they are both output at the same frequency. IMAGE