| 摘要 |
PURPOSE:To cancell the distortion in a stereophonic demodulating signal produced by a band pass filter of an intermediate frequency stage by adding or subtracting a receiving signal and an output signal of a multiplier circuit whose level is adjusted and providing a coupling circuit applying an output signal to a stereo demodulating circuit. CONSTITUTION:A main signal S1 extracted by a main signal extracting circuit 2 and a double side band signal S2 extracted by a double side band signal extracting circuit 3 are applied to a multiplier circuit 6 and multiplied together and an output signal S3 of the level adjusting circuit 7 is applied to a subtraction circuit 4 where an output signal S4 is subtracted from an FM demodulating signal SD. An output signal S5 of the subtraction circuit 4 is applied to a stereo demodulating circuit 8 where the signal is stereo-demodulated. In taking the input/output level ratio of the level adjusting circuit 7 as l(=16k), the distortion component in the output signal S5 of the subtraction circuit 4 is made zero and cancelled and the 2nd harmonic distortion does not exist in the stereophonic demodulation signal. |
