| 摘要 |
PURPOSE:To improve the distortion of reproduced signal due to phase modulation of a limiter circuit, by applying the output signal of an intermediate frequency signal passing filter to the limiter circuit via a level correcting circuit. CONSTITUTION:The output signal of an intermediate frequency signal passing filter 2 is fed to an amplitude modulating circuit 5, the output signal of the filter 2 is fed to a negative amplitude detecting circuit 7 via a variable gain amplifying circuit 6, and the AC component obtained at the output side of the circuit 7 is fed to the input terminal of modulation signal in the circuit 5. Further, the DC component obtained at the output side of the circuit 7 is fed to the control terminal of the circuit 6 via an automatic gain control circuit 8. Thus, the detection output signal independently of the input signal level as the AC component of the output signal of the circuit 7 can be obtained and the output signal of the filter 2 is inversely modulated with this signal. Accordingly, the amplitude modulation level at the circuit 5 can be made shallow remarkably. Since the output signal of the circuit 5 is fed to the limiter circuit 5, the phase modulation component in the circuit 3 can be made less. |
