Patent ID: 7295821

Claim:
An automatic frequency control (AFC) system applied in a mobile station of a wireless cellular system for automatically controlling a local frequency signal (f L ) to be substantially synchronized with an input signal (S I ) which is a first received signal (S H ) from a first base station and being capable of shifting the frequency of the local frequency signal (f L ) to be close to that of a second received signal (S new ) from a second base station when the input signal (S I ) is changed from the first received signal (S H ) to the second received signal (S new ), the system comprising: an automatic frequency controller for receiving the input signal (S I ) and generating the local frequency signal (f L ); a memory unit for storing a plurality of AFC parameter sets, each AFC parameter set being corresponding to a base station within the wireless cellular system; and a control module; wherein when the input signal (S I ) is changed from the first received signal (S H ) to the second received signal (S new ), the control module fetches the AFC parameter set, which corresponds to the second base station, from the memory unit and applies the fetched AFC parameter set, which corresponds to the second base station, to the automatic frequency controller to shift the frequency of the local frequency signal (f L ).