JPS6439188A - Ringer signal generating circuit - Google Patents

Abstract

PURPOSE:To speed up the rise-up of a ringer signal by charging, at a constant voltage beforehand, a capacity element to connect first and second amplifying circuits while a signal is not sent out. CONSTITUTION:A power source switch 3 is normally turned off for an energy saving, while a charging switch is turned on. When a ringer actuating signal is received from a slave station, the switch 3 is turned on to activate amplifying circuits 4 and 5, the switch 9 is turned off, a signal from an oscillating circuit 1 is inputted to the non-inverse input terminal of the circuit 4, further is amplified and the signal of an equal phase is turned to be one output. Further, the output is partial-pressured, dropped to a level almost same as an input signal and a direct current cutting is executed by a capacitor 8. Since the capacitor 8 is charged at that time, the signal of the circuit 4 is inputted to the inverse input terminal of the circuit 5 simultaneously with the output of the signal of the circuit 4 and turned to be another output having the phase difference of pi. The difference between these two output signals is turned to be the output of a ringer generating circuit and the bell of a telephone set is rung.