| 摘要 |
PURPOSE:To improve the separation degree of signals throughout a range from the weak signal input level to the strong signal input level, by controlling the gain of the FM or PM detecting circuit for obtaining a stereo difference signal according to the input level. CONSTITUTION:A DC voltage proportional to the stereo sum signal output from AM detecting circuit 13 is generated by low-pass filter 20. This DC voltage is fed back to higher harmonic amplifying circuit 11 and intermediate frequency amplifying circuit 12 to control the gain and the amplitude of separation degree compensating circuit 30 which amplifies the stereo difference signal obtained by FM detecting circuit 15, thereby equalizing amplitudes of the stereo difference signal and the stereo sum signal. |
