Circuit for synchronizing CDMA mobile phones

摘要

A frequency calibration circuit for use in a spread spectrum receiver. The receiver includes circuitry for receiving a spread spectrum signal from a base station and for recovering a network clock signal therefrom, a low frequency oscillator for producing an oscillator clock signal, and a frequency comparator that takes as inputs the network clock signal and the oscillator clock signal and produces a calibration factor based on the difference between the clock signals. A controller coupled to the low frequency oscillator amd the frequency comparator utilizes the calibration factor together with the low frequency oscillator clock signal to output a accurate and precision timed signal thereby being able to accurately require the timing of the paging channel.