Patent ID: 7138838

Claim:
A phase locked loop, comprising: a phase-frequency detector that detects a phase difference between a reference signal introduced into a first input terminal and an input signal introduced into second input terminal, and that generates output pulses according to the phase difference; a charge pump that outputs electric current according to an output signal from the phase-frequency detector; a loop filter that attenuates a charge pump output of the charge pump; a voltage controlled oscillator in which the frequency of an oscillator output signal is controlled according to an output voltage of the loop filter; a programmable divider which divides the oscillator output signal from the voltage-controlled oscillator according to input division number data and feeds it back to the second input terminal of the phase-frequency detector; a first modulator that transforms an incoming baseband signal into an integer signal for specifying a division number and that sends the integer signal to a control terminal of the programmable divider; a second modulator which shapes the incoming baseband signal into a prescribed signal waveform and sends it to the voltage controlled oscillator; and a controller which adjusts a phase error between the first modulator and the second modulator.