| 摘要 |
PURPOSE:To improve the eliminating capacity of an impulsive noise eliminating circuit, by arranging a filter circuit, which stops the passage of a continuously generated impulsive noise signal when this signal is received, in the output side of a single-generated noise pulse eliminating circuit. CONSTITUTION:When a single impulsive noise signal is included in the wave detection output from a wave detecting circuit 1, the output of a noise amplifier 8 is not changed much, and therefore, the level of the amplification degree control signal of an amplification degree controlling circuit 10 is low, and a switching transistor TR 14 is turned off, and a filter circuit 11 does not function. Consequently, the held level signal of a capacitor 4 for holding the storage which is provided in the output side of a switch 3 for eliminating the single noise pulse is sent to a voice part 6 as it is. When a continuously generated impulsive noise is included in the wave detection output, the switching TR 14 is turned on, and therefore, the noise signal which passes through the switch 3 erroneously is eliminated by a low pass filter consisting of a resistance 12 and a capacitor 13 and is not sent to the voice part 6. |
