Patent ID: 7741889
Filing Date: 2010-06-22
Classification: H03L

Abstract:
1. A phase-locked loop with phase rotation for spreading spectrum, comprising: a phase detector, which receives a reference clock signal and a feedback clock signal to thereby produce an error signal; a charge pump, which is connected to the phase detector in order to convert the error signal into a current signal; a filter, which is connected to the charge pump in order to convert the current signal into a voltage signal; a voltage-controlled oscillator (VCO), which is a ring oscillator connected to the filter in order to produce N clock signals with a same frequency based on the voltage signal, wherein the N clock signals have phases θ a selector, which is connected to the VCO in order to select one from the N clock signals based on a predetermined sequence to thereby produce a target clock signal; wherein the selector sequentially selects the clock signals with the phases θ