| 摘要 |
<p>PURPOSE:To prevent a speaker SP from generating a sound owing to a noise component in case of a break of a receive input level by continuing the operation of a transmit power source part for a specific time after the end of a telephone talk, and inserting a low frequency delay circuit which has proper delay time between a frequency discriminating circuit and a low frequency amplifier of a reception part. CONSTITUTION:A noise component obtained from the frequency discriminator DISC when a receive radio wave breaks on the talk with an opponent station is applied to a speaker SP through the low frequency amplifier AMP almost without being delayed as well as a voice signal. For this purpose, the low frequency delay circuit DL is inserted between the frequency discriminator DISC and low frequency amplifier AMP and the delay time of this delay circuit is set to a proper value to delay the whole waveform, so that the operation-off point of the low frequency amplifier AMP is set within the delay time. Thus, the delay time of the low frequency delay circuit DL Is set to prevent the speaker SP from being driven by a noise component in case of a break of the receive input level, so that the speaker SP generate no sound.</p> |
