US Patent 7187915 Automatic gain control for a WLAN system

An Automatic Gain Control (AGC) method and system thereof. The power of a detected signal is first checked to ensure that it is large enough for AGC process. A power average of the detected signal is computed and compared to a first threshold in order to determine whether to proceed with a coarse tune procedure or enter a fine tune procedure. Both Low Noise Amplifier (LNA) gain and Variable Gain Amplifier (VGA) gain are tuned during coarse tune, whereas only the VGA gain is tuned during fine tune. The LNA and VGA gains are tuned to predetermined values during coarse tune, and the VGA gain is adjusted according to a difference between a computed average of power and a second threshold.