| 摘要 |
PURPOSE:To receive and reproduce a transmission output of plural wireless microphone equipments without interference by setting the equipment in the sweep state automatically when no identification signal superimposed onto a received voice signal is detected. CONSTITUTION:With a switch 20 turned on, a control section 19 is set to the automatic sweep state, the frequency division ratio of a programmable frequency divider 14 is varied automatically at a prescribed period to apply the automatic sweep. When being tuned to a voice sending signal superimposed with the identification signal from a microphone equipment, a sweep stop signal (s) is supplied from an intermediate frequency amplifier section 22 to the control section 19 to stop the frequency division ratio variable operation. The signal (s) is fed to a NOR gate 30 together with an output of an identification signal detection circuit 24 via a differentiation circuit 26 and a pulse generating circuit 31 is not triggered by an L output of the gate 30. When the transmission from the microphone equipment is stopped and no identification signal is detected, the circuit 31 is triggered, a transistor 33 is turned on and the switch 20 is in the equivalent state as the ON-state to attain automatic sweep state, and the reception/ reproduction without interference with the transmission output of the microphone equipments is attained. |
