| 摘要 |
PURPOSE:To improve squelch operation by utilizing an ATIS (Automatic Transmitter Identification System) signal modulated to a transmission signal of a personal radio equipment or the like to add a kind of an identification signal to the ATIS signal. CONSTITUTION:In a radio system transmitting automatically an identification code such as ATIS signal at the start, middle and end of talking, the identification signal 10 representing the middle to the ATIS signal at the middle other than the start and end of the talking is added. A receiver identifies the ATIS signal and also detects the identification signal 10, neglects the ATIS signal with respect to squelch function for a prescribed time from the carrier leading and the squelch function is closed by taking it as the notice of carrier interruption if no identification signal 10 is detected in the succeeding ATIS signal. Since a sound output circuit is closed already for noise generated at carrier interruption, no noise is outputted from a speaker. On the other hand, since the ATIS signal is not identified against momentary electric field reduction such as fading, the squelch function is not interrupted. |
