| 摘要 |
PURPOSE:To reduce switch noise, by providing a second switch which selects and outputs the output signal of a delay unit or that of a level holding unit, and shortening a level holding interval. CONSTITUTION:After the higher FM carrier component of an FM demodulation voice signal is eliminated by a low-pass filter 53, the just before value at a point where the switch noise is generated is inputted to the level holding unit 54, and is held at that level, and the FM demodulation voice signal is delayed, and is matched with temporal timing at a position where the switch noise is generated of the output signal of the low-pass filter, and the switch noise interval of a delayed FM demodulation voice signal is held at the level held at the level holding unit 54. Since the delayed FM demodulation voice signal does not pass a filter, a very short interval to hold the switch noise is enough, and furthermore, since the impulsive switch noise has been already removed, the interval to hold the noise is not extended further even when it passes the filter for eliminating an FM carrier component hereafter. Consequently, it is possible to shorten the interval to hold the noise, and to reduce the switch noise.
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