In some implementations, an automatic gain control (AGC) circuit comprises: a pre-divider circuit operable to pre-divide an input signal according to a pre-divider circuit setting and output a pre-divided signal; a pre-amplifier operable to pre-amplify the pre-divided signal and output a pre-amplified signal; a post-divider circuit operable to post-divide the pre-amplified signal according to a post-divider circuit setting; an analog-to-digital converter (ADC) operable to generate a digital data stream from the post-divided signal; logic operable to sample the digital data stream; determine a pre-divider circuit setting and a post-divider circuit setting based on the sampled data stream; set the pre-divider circuit and the post-divider circuit based on the determined settings; and generate a received signal strength value based on the pre-divider circuit setting and the post-divider circuit setting.

A receiver, including: a tuner receiving an input signal; a signal processor configured to process the input signal; an automatic gain control (AGC) controller configured to: initialize the receiver in a low gain state; determine the presence of a signal; and increase the receiver gain to determine if a weak signal is present prior to a strong signal.

In some implementations, an automatic gain control (AGC) circuit comprises: a pre-divider circuit operable to pre-divide an input signal according to a pre-divider circuit setting and output a pre-divided signal; a pre-amplifier operable to pre-amplify the pre-divided signal and output a pre-amplified signal; a post-divider circuit operable to post-divide the pre-amplified signal according to a post-divider circuit setting; an analog-to-digital converter (ADC) operable to generate a digital data stream from the post-divided signal; logic operable to sample the digital data stream; determine a pre-divider circuit setting and a post-divider circuit setting based on the sampled data stream; set the pre-divider circuit and the post-divider circuit based on the determined settings; and generate a received signal strength value based on the pre-divider circuit setting and the post-divider circuit setting.

According to one embodiment, an amplification circuit includes an amplifier having a gain based on a gain control signal and amplifying an input signal by the gain, and a control portion outputting the gain control signal for increasing the gain after decreasing the gain based on an amplitude of the input signal, when the amplitude of the input signal is detected.

According to one embodiment, an amplification circuit includes an amplifier having a gain based on a gain control signal and amplifying an input signal by the gain, and a control portion outputting the gain control signal for increasing the gain after decreasing the gain based on an amplitude of the input signal, when the amplitude of the input signal is detected.

An RF unit receives predetermined signals. The RF unit amplifies the received signals. A gain control unit controls the gain at the RF unit based on the amplified signal and has the RF unit use the controlled gain. The gain control unit performs different controls on the received signals, depending on the case when the received signal is a known signal placed in the beginning of packet signal and the case when the received signal is a signal other than the packet signal.

A reception device includes a low noise amplifier that amplifies a radio signal by a first gain, a variable gain amplifier that amplifies an output of the low noise amplifier by a second gain, an analog-to-digital converter that converts an output of the variable gain amplifier into a digital signal, a gain controller, and a saturation detection unit. The gain controller, when an amplitude of the radio signal exceeds a predetermined value, controls the first and second gains according to the amplitude of the radio signal, and completes the control within a predetermined period. The saturation detection unit detects saturation of the analog-to-digital converter based on the output of the low noise amplifier or the digital signal. The gain controller, after controlling the first and second gains a first time and the saturation is detected by the saturation detection unit, controls the first and second gains a second time.

The present invention relates to a method and device for performing automatic gain control. The method comprises predicting an AGC setting to be used based on statistical data with respect to a plurality of previously stored AGC settings. The method also comprises receiving an interference signal during an idle time period using the predicted AGC setting. The method further comprises detecting received power of the interference signal. The method additionally comprises adjusting the predicted AGC setting based on a result of the detecting. With the method and device of the present invention, an initial AGC setting with high accuracy and usability can be obtained and the glitch effect can be overcome.