Patent ID: 7308238

Claim:
A mobile terminal, comprising: a complex correlator which detects a control signal from a base station; an automatic frequency controller which detects a current peak position value from the control signal and calculates an AFC (Automatic Frequency Control) voltage based on a difference value (dev) between the current peak position value and a previous peak position value; and an oscillator which generates an oscillation frequency for controlling a demodulator based on the AFC voltage, wherein the automatic frequency controller comprises: a peak detector which detects the current peak position value from the control signal; a peak period deviation detector which subtracts the previous peak position value from the current peak position value to calculate the difference value (dev); a zero counter which counts a number of successive 0s in the difference value (dev) and outputs a zero-run value; and an AFC mapping unit which converts the difference value (dev) and the zero-run value into digital AFC voltages.