POWER SAVING TYPE RADIO DUPLEX TRANSMITTER AND RECEIVER

摘要

PURPOSE:To reduce the power consumption of radio duplex transmitter and receiver without decreasing its S/N ratio, by using a compressor and an expander for the companding of an input and an output signal, and further controlling a transmission output according to the intensity of a modulated input. CONSTITUTION:A modulated signal input 1 has input level variation compressed at a specified rate through a compressor 2, and is transmitted to opposite-side ratio equipment through a transmitter 3, an antenna common-use device 4, and an antenna 5. A modulated input detecting circuit 9 monitors the signal level of the input 1. The transmitter 3 is so controlled by a control circuit 10 that when the signal level is higher than a specified value, the transmission output of the transmitter 3 has a rate level. When the signal level is lower than the specified value, e.g. when no signal is inputted, the control circuit 10 performs control so that the transmission output of the transmitter 3 has a level, e.g. one-tenth as high as the rated level. A signal from the opposite-side radio equipment is demodulated through a receiver 6 and an expander 7.