Ear inserting type transmitter-receiver

摘要

An ear inserting type transmitter-receiver of full duplex system comprises an ear piece, a sound converting element, an impedance element, an electric signal applying means for applying an electric signal based on a first voice signal to a series circuit of the sound converting element and the impedance element, a detecting means for detecting the voltage across the sound converting element, an analog/digital converting means for converting the electric signal based on the first voice signal into a digital signal, an analog/digital converting means for converting a sound converting element terminal signal to a digital signal, a digital signal operational processing means for extracting a second voice signal from the sound converting element terminal signal based on output signals from the two analog/digital converting means and a digital/analog converting means for converting a digital signal of the second voice signal thus operated into an analog electric signal so as to function in common as a microphone and an earphone by means of the single sound converting element. <IMAGE>