| 摘要 |
PURPOSE:To obtain an interruption circuit without deterioration quality of call by connecting a transmission amplifier circuit of high output impedance via a receiving amplifier circuit of high input impedance in the interrupting connection to a line during communication. CONSTITUTION:The transmission amplifier circuit 24 of feedback type having a high output impedance and the receiving amplifier circuit 25 of high input impedance are connected to interrupting terminals 29, 30 via an unbalancing/balancing converting circuit 23 and an output of the receiving amplifier circuit 25 is connected to an output terminal 28 via a return loss compensating circuit (side tone preventing circuit) 26. A voice signal from an input terminal 27 is transmitted to the interruption terminals 29, 30 and the voice signal at the interruption terminals 29, 30 is outputted from the terminal 28, but since the interruption circuit viewed from the interruption terminals 29, 30 has high impedance, the deterioration of quality of communication caused by impedance mismatching due to interruption connection is produced. |
