| 摘要 |
PURPOSE:To eliminate troubles of correspondence using predetermined carrier waves, by fixing th carrier wave selected at a sequence circuit by a received radio signal with respect to a press-to-talk single channel radio communication system. CONSTITUTION:Carriers f1, f2, f3... are outputted from a synthesizer 14 according to the sequence, and radio frequencies are demodulated into each IF signal with the carriers f1, f2... inputted to frequency converting circuits 13 and 19. When a specified IF signal among the IF signals detects a reception signal 16 at a demodulator 15, the intermission of the reception signal 16 is compensated at a timer 25, an output of the said timer 25 turns off a gate circuit 23 and stops a clock 22 outputted from the said circuit 23, and the advancement of a ring counter 25 is stopped. The frequency data of a preset circuit 3 is fixed to fix the carrier outputted from the frequency synthesizer 14. |
