OSCILLATION PREVENTING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide an oscillation preventing circuit that attains a stable two- way speech without causing oscillation between transmission/reception sections of both communication units where a transmission section and a reception section are installed at the same place or close to each other without the need for gain adjustment to prevent the oscillation. SOLUTION: The oscillation preventing circuit is used for communication between two points where one communication unit and other communication unit are connected via a transmission system 31 to attain 2-way communication. The oscillation preventing circuit is provided with switch circuits 38, 42 that are respectively provided to a transmission section 32 and a reception section 33 to turn on/off the flow of a signal and with a control circuit 45 that controls the switch circuits so that the switch circuit of the reception section is turned off when the switch circuit of the transmission section is turned on and the switch circuit of the reception section is turned on when the switch circuit of the transmission section is turned off in a way that both the switch circuits are not simultaneously turned on.