ELECTRONIC DEVICE INCLUDING FREQUENCY SYNTHESIZER AND CONTROL METHOD FOR THE FREQUENCY SYNTHESIZER

摘要

PROBLEM TO BE SOLVED: To provide an electronic device that decides whether or not a capacitor or other component able to change an oscillating frequency of an oscillator is to be inserted to or withdrawn from a circuit of a variable oscillator. SOLUTION: This electronic device includes a frequency synthesizer which adopts phase control acting on an oscillator 22, based on substantially a phase detector 26. In order to ensure that the oscillator oscillates at an assigned frequency band, switching capacitors 38, 39, 40, 41 are added to the electronic device, the capacitors are inserted to an oscillating circuit for the oscillator 22 as a function of the count in an up/down-counter 77. This electronic device is applicable to a portable radio telephone set.