| 摘要 |
PURPOSE:To prevent the frequency characteristic of a reproducing signal from deteriorating by controlling a characteristic of an adaptive equalizer by an output of a comparison circuit for comparing an FM carrier level of the reproducing signal with a lower side-band level and consequently minimizing the lower side-band level to be smaller than the carrier level by an output of the equalizer. CONSTITUTION:A reproducing signal reproduced by a reproducing head is amplified by a head amplifier 2 and inputted to an adaptive equalizer 3 and also to a level comparator circuit 4. A lower side-band frequency is filtered by a BPF 5 of this circuit 4, while an FM carrier frequency is filtrated by a BPF 6 and they are detected by their respective detectors 7 and 8 and compared each other in level by a comparator 10. By a comparison output of the circuit 4 a characteristic of the equalizer 3 is controlled in order to control an output of the equalizer 3 to obtain the FM carrier level to be small. The frequency characteristic of the reproducing signal after demodulation is prevented from deteriorating, and when the carrier frequency level is lowered by the compatible reproduction, etc., a stable reproducing picture is outputted accordingly.
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