| 摘要 |
PURPOSE:To perform FM reception with good sense of listening, by performing the detection of a distorted component from an AGC signal of an intermediate frequency amplifier section and controlling the degree of stereophonic separation and the tone of a detecting circuit. CONSTITUTION:The AGC signal obtained from a terminal (d) of the intermediate frequency amplifier section 3 of an FM receiving section 8 is applied to an amplifier circuit 15 via an LPF17 and an HPF. When the FM receiving section 8 is subjected to multipath and a voltage standing wave, the AGC signal is fluctuated by them, the distorted component is applied to the amplifier circuit 15. This component of distortion is applied to an automatic stereophonic separation controlling and driving circuit 12 and an automatic tone adjustment controlling and driving circuit 13 via an amplifier circuit 17' and a detecting circuit 16. These circuits 12, 13 decrease the degree of stereophonic separation at an FM stereophonic demodulating section 5 depending on the amplitude of the component of distortion and decreases the tone. In this case, the restoration of the degree of stereophonic separation and the tone when the distortion signal is lost is controlled so as to be done gradually. |
