| 摘要 |
PURPOSE:To prevent inversion phenomena of an input/reproduced FM signal without causing deterioration in the resolution or S/N by controlling dynamically the cut-off frequency and the attenuation amount of a high-pass filter corresponding to the levels of an input/reproduced FM signal. CONSTITUTION:The followings are provided: a first subtractor 2, a low-pass filter 3, a second subtractor 4, a first adder 5, a second limitor 6, a third subtractor 7, a first limitor 8, and a second adder 9. And the gains of the two limitors 6, 8 are controlled corresponding to the levels of an input/reproduced FM signal, so that the cut-off frequency and the gain of the high-pass characteristic comes lower when the input level is high, and inversely, when the input level is low, the cut-off frequency and the gain comes higher. As a result, the inversion phenomena of the signals can be prevented without causing deterioration in the resolution or S/N.
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