Patent ID: 6169457
Filing Date: 2001-01-02
Classification: H03L

Abstract:
A frequency synthesizer comprising: an oscillator which outputs an output signal, a frequency divider which divides the output signal from the oscillator so that its frequency division value is in periodic variation to generate a comparative signal, a phase comparator which compares the phase of the comparative signal with the phase of a reference clock signal, and controls the aforementioned oscillator such that the oscillator output signal becomes a frequency that equals the frequency of the reference clock signal times the average frequency division value, and a phase compensation circuit connected to the transmission path of the signal that controls the oscillator from the phase comparator wherein the phase compensation circuit comprises: a plurality of capacitors with one end connected to the transmission path of the signal that controls the oscillator from the phase comparator, at least two voltage sources connected to the other end of the capacitors through a plurality of switches, and a voltage controller to control the switches.