RECEIVING SECTION OF TELEPHONE SYSTEM

摘要

PROBLEM TO BE SOLVED: To prevent influence of improper audible noises which are generated by an electrical disturbance during transient period by adding a delay means to a controller, to generate the control signals to the 1st and 2nd enable/disable means in accordance with a prescribed control program and also to generate control signal of a switching means. SOLUTION: A processor 11 receives a demodulated digital signal RX-IN at its input side and supplies an analog signal, that is balanced between two outputs. The output of the processor 11 is connected to the input side of a differential amplifier 12 and then connected to one of input sides of the amplifier 12 through the resistances R1A and R1B connected in series to the MOS transistor M1A and M1B. An electroacoustic transducer 13 is connected between the output sides 15 and 16 of the amplifier 12. The processor 11 and the amplifier 12 have a circuit means to enable or disable a power supply in accordance with the signals which are applied to the corresponding enable terminals 17 and 18 respectively.