Patent ID: 7363013
Filing Date: 2008-04-22
Classification: H03C

Abstract:
1. A phase lock loop for receiving a baseband signal having an input frequency and modulating the baseband signal to be a corresponding RF signal for transmitting, the phase lock loop comprising: a frequency synthesizer for generating a local oscillating signal having a local oscillating frequency; a first programmable divider for dividing the frequency of the local oscillating signal by a first programmable divisor to generate a reference signal; a modulator for modulating the reference signal according to the baseband signal to generate a first comparison signal; a phase detector for generating a phase difference signal for representing the phase difference between the first comparison signal and a second comparison signal; a charging pump for receiving the phase difference signal and accordingly outputting a control current; a loop filter for filtering the control current to output a control voltage; an oscillating signal generator for generating the corresponding RF signal having a frequency in responsive to the control voltage, the RF signal being fed back as a feedback signal; and a frequency converter for receiving the feedback signal and the local oscillating signal to output the second comparison signal to the phase detector in responsive to the frequency difference between the feedback signal and the local oscillating signal; wherein the first programmable divisor of the first programmable divider and the local oscillating frequency of the local oscillating signal, which is corresponded to said first programmable divisor, are capable of being programmable-controlled only if a carrier frequency of the RF signal substantially equals to a predetermined value.