FREQUENCY VARIABLE SYSTEM, VOLTAGE-CONTROLLED OSCILLATOR ADOPTING THE SAME, AND RECEIVER FOR SPREAD SPECTRUM COMMUNICATION USING THE SAME

摘要

PROBLEM TO BE SOLVED: To use a crystal resonator which is the component of the voltage controlled oscillator, whose oscillated frequency is changed and a crystal resonator of an oscillator generating a fixed frequency in common.;SOLUTION: An integration device 12 integrates a control input, and frequency is varied by controlling the phase of a frequency division signal obtained by frequency-dividing a clock with a fixed frequency with a frequency divider 11, based on the integral value. Every time a phase shift amount reaches the that of one clock portion, a frequency division ratio used to frequency-divide the clock is changed from a prescribed frequency division ratio by one frequency division, to absorb a phase shift amount by one clock portion, thereby acting the circuit as a voltage controlled oscillator. Thus, the voltage-controlled oscillator is realized, where precision of a fixed frequency of the clock is maintained.;COPYRIGHT: (C)2000,JPO