Patent ID: 8301096

Claim:
An automatic gain control method, comprising: (a) adjusting a gain of a received signal in a finding mode, while additionally changing the gain at least once according to a variation condition of a gain curve of the gain such that the gain approaches a target gain level, wherein the step of additionally changing the gain comprises the sub-steps of: detecting at least one characteristic point of the gain curve, wherein the at least one characteristic point of the gain curve comprises at least one point of the gain curve, at which a first order or a second order differential of the gain curve with respect to time is equal to zero substantially; determining a switching value for making the gain approach the target gain level according to a gain of the gain curve corresponding to the at least one point; and setting the gain to a new gain according to the switching value and making the new gain become valid; wherein the detecting, determining and setting sub-steps are performed at least once.