Patent ID: 7076221

Claim:
A digital automatic fine tuning method, comprising the steps of: setting a frequency detection resolution â€˜aâ€™ of an Intermediate Frequency (IF) signal and a nominal frequency f 0 ; calculating a reference counted value X from the nominal frequency f 0 and the detection resolution â€˜aâ€™ according to the follow Equation, X:f 0 =X+1:f 0 +a, and a window period â€˜bâ€™ which is time required to count to the reference counted value X; receiving an IF signal; resetting a window counter for counting the window period and a frequency counter unit for counting a frequency to respective initial values; counting frequency detection time using the window counter and a frequency of the received IF signal using the frequency counter unit; determining whether a counted value of the window counter reaches the calculated window period â€˜bâ€™; if it is determined that the counted value of the window counter reaches the window period â€˜bâ€™, detecting a counted value â€˜dâ€™ of the frequency counter unit; and outputting an automatic fine tuning signal corresponding to a difference between the detected counted value â€˜dâ€™ and the calculated reference counted value X and returning to the step of resetting.