| 摘要 |
PURPOSE:To eliminate the interruption of relaying from the start of a master station to the start of the transmitter of a relay station by starting temporarily the transmitter only with a noise detection output,interrupting the relaying when no tone reception is confirmed and keeping the relaying when confirmed. CONSTITUTION:A timer circuit 6 is started by the output signal A of a noise detection circuit 1 to output a signal D. The time width t2 of a signal D is set slightly larger than a time delay t1 produced by a narrow band filter 2. Since the transmitter Tx is started successively from a reception wave input point of time, the delay in the relay time by the delay time t1 is eliminated. When the reception wave input exists and no tone signal is received (figure c), since the output signal B of a tone detection circuit 3 does not rise, the signal C falls down after the time t2, resulting that the relaying is interrupted. |
