| 摘要 |
PURPOSE:To reduce a moltipath noise, by always comparing and operating a signal level and a multipath signal level, and executing the attenuation of a high-frequency component and a blending operation between right and left channels. CONSTITUTION:An output signal (intermediate frequency signal) from the first amplifying circuit 4 is provided to an IF1 terminal, an output signal from the second amplifying circuit 5 is provided to an IF2 terminal, each signal is detected by diodes D1-D3, and an IF signal level V2 is detected in a variable resistance VR2. The detected signal is amplified by a transistor T and is rectified by diodes D4, D5, and as a result, an amplitude modulation portion in the IF stage is taken out by a VR1, and is detected as a multipath signal level V1. V2 and V1 are compared by an operational amplifier 8, and its output voltage V0 becomes control voltage of a multiplexer 7. In case when V0 is low, the poststage is set so that the attenuation of a high frequency component or a blending operation between right and left channels is executed. |
