Circuit arrangement comprising a voltage-controlled oscillator operable

Abstract

In a circuit arrangement comprising a power source circuit (12) and a phase detector (22), a phase difference signal (PD) is supplied to a first switch (31) repeatedly turned on and off during battery saving operation and to a second switch (32) initially turned on simultaneously with the first switch. First and second intermediate signals are sent through first and second low-pass filters (41, 42; 43, 44) as first and second modified signals (MO.sub.1 and MO.sub.2), respectively, to a voltage-controlled oscillator (25). A bidirectional nonlinear circuit (36, 37) becomes conductive and also sends the second modified signal to the voltage-controlled oscillator when the first intermediate signal becomes high. The voltage-controlled oscillator produces an oscillation signal with a high sensitivity on supply of both the first and the second modified signals and with a low sensitivity on sole supply of the first modified signal. Such different sensitivities serve to make the circuit arrangement rapidly and stably carry out the battery saving operation.