| 摘要 |
PURPOSE:To stop the transmission of a digital selective calling signal at a transmitter side automatically when an opposite station of communication is a radio equipment having no digital selective calling function by providing a switch circuit to a demodulation section of a MODEM and a digital signal system. CONSTITUTION:The radio equipment consists of a modulation section 6, a reception high frequency section(RF) 7, an intermediate frequency amplifier section(IF) 8, a low frequency amplifier section(AF) 9, a squelch section 10, a ROM 11, an MPU 12, a modulation section 13 for a digital signal processing MODEM, a switch circuit 14 operated by a command from the MPU 12, a demodulation section 15 for the MODEM, a microphone input terminal 16 and a voice signal output terminal 17 or the like. Then the demodulation section(DEM) 15 demodulates and decodes an ACK signal from an opposite station and sends the result to the MPU 12, analyzes the presence of the ACK signal to activate the switch circuit 14. That is, since the switch circuit 14 is opened in the absence of the ACK signal, the modulation of the digital selective calling signal is stopped. |
