OSCILLATOR AND PHASE-COHERENT LOOP

摘要

PROBLEM TO BE SOLVED: To reduce phase noise of an oscillator and to reduce power consumption and phase noise of a phase-coherent loop.;SOLUTION: The oscillator is so configured as to vary in oscillation frequency according to a capacitance value of a resonant circuit, and includes an accumulator 11 that intermittently outputs an overflow signal according to an external clock input from outside and set data, a switch 12 which is turned on/off according to the intermittent input of the overflow signal, and a capacitive element C2 having a fixed capacitance value that is connected to the resonant circuit via the switch 12. An average oscillation frequency is varied in compliance with the ratio of the on-time to the off-time between the oscillation frequency in an on-time wherein the switch 12 is turned on by the input of the intermittently output overflow signal according to the set data and the oscillation frequency in an off-time wherein the switch 12 is turned off when there is no input of the overflow signal.;COPYRIGHT: (C)2010,JPO&INPIT