Phase-locked loop frequency synthesizer of fractional N-type, and phase shift circuit with frequency converting function

摘要

Provided is a phase-locked loop frequency synthesizer, including: a reference oscillator; a voltage controlled oscillator; a variable frequency divider that divides the high frequency signal in frequency to output a feedback signal; a phase comparator that compares the reference signal and the feedback signal with each other to output a phase comparison signal; a loop filter that outputs a control signal of the voltage controlled oscillator based on the phase comparison signal; and a frequency/phase control circuit that generates frequency division number control data in synchronism with any one of the feedback signal and the reference signal based on setting data which is input from an external to give an output frequency and setting data which is input from the external to give a phase to the reference signal, to thereby output the frequency division number control data to the variable frequency divider.