Patent ID: 6498536
Filing Date: 2002-12-24
Classification: H03L,Y10S

Abstract:
An oscillating circuit for producing an output signal synchronous with an input signal, comprising:a signal input node effective to receive said input signal; a voltage-controlled oscillator including a feedback loop having voltage-to-frequency characteristics achieved in a certain control range, and responsive to a control voltage signal effective to change a frequency of said output signal; a control loop connected to said signal input node and said voltage-controlled oscillator so as to compare said frequency of said output signal with a frequency of said input signal to see whether the difference between said input and output signals falls within said certain control range, and changing a first sub-signal of said control voltage signal so as to make said frequency of said output signal substantially coincident with said frequency of said input signal when said difference is out of said certain control range; and said feedback loop is connected to said signal input node and said voltage-controlled oscillator, and controls said voltage-controlled oscillator with a second sub-signal of said control voltage signal so as to make said output signal and said input signal in-phase when said difference is within said certain control range.