Patent ID: 6657986
Filing Date: 2003-12-02
Classification: H04B,H04J

Abstract:
A method for correlating a received signal with a locally generated signal at a first clock rate during a signal acquisition mode, and at a second clock rate during a locked signal mode using a correlation circuit the method comprising the steps of:operating in said signal acquisition mode, comprising the steps of: providing said received sign; generating, at said first clock rate, said first local signal; correlating, at said first clock rate, said received signal with said first local signal to produce a fist cross-correlation product, said first cross-correlation product indicating that said received signal and said first local signal are aligned within a predefined range; and after said received signal and said first local signal are aligned within the predefined range, operating in said locked signal mode, comprising tee steps of: providing said received signal; generating, at said second clock rate, a second local signal, wherein the second clock rate is less than the first clock rate; and correlating, at said second clock rate, said received signal with said second local signal to produce a second cross correlation product, wherein the correlation circuit consumes less power correlating said received signal with one of said local signals at said second clock rate than at said first clock rate.