Patent ID: 7777586

Claim:
A multi-band electronic apparatus, comprising: a first circuit, comprising: a first voltage controlled oscillator, outputting a first output signal in a first band according a control voltage; and a first switch set, coupled to the first voltage controlled oscillator, selectively enabling the first voltage controlled oscillator to output the first output signal; according to a switch control signal; a second circuit, comprising: a second voltage controlled oscillator, outputting a second output signal in a second band according the control voltage, wherein the first and second bands are not completely overlapped; a second frequency divider, coupled to the second voltage controlled oscillator, dividing frequency of the second output signal to output a second frequency divided signal; and a second switch set coupled to the second voltage controlled oscillator and the second frequency divider, selectively enabling the second voltage controlled oscillator to output the second output signal and the second frequency divider to output the second frequency divided signal; a third circuit, comprising: a first frequency divider, dividing frequency of the first output signal or the second frequency divided signal to output a first frequency divided signal; a phase detector, coupled to the first frequency divider, receiving the first frequency divided signal and a reference signal, determining a phase difference between the first frequency divided signal and the reference signal to output a phase difference signal; and a loop filter, coupled to the phase detector, outputting the control voltage according to the phase difference signal.