Patent ID: 8364109

Claim:
A receiver, comprising: an amplifier module, for amplifying an input signal, comprising a plurality of amplifier units which are coupled in parallel and have different gains; a control unit for enabling at least one of the amplifier units according to a gain control signal, wherein the enabled at least one amplifier unit generates an output RF signal in response to the input signal; a mixer coupled with each of the amplifier units in series and for down-converting the output RF signal to an IF signal according to a local oscillation frequency; and an IF amplifier with a variable gain coupled to the mixer for amplifying the IF signal to an output signal according to the gain control signal under the control of the control unit; wherein, the control unit obtains the gain control signal according to the output signal and a reference signal; and the control unit comprises: a pre-segmenting unit for receiving the gain control signal and generating a segment tuning control signal according to the gain control signal; a scale transformer for adjusting the segment tuning control signal, so that a slope of the segment tuning control signal is not smaller than a slope of the variable gain of the IF amplifier; and a selector for receiving the gain control signal and the segment tuning control signal, wherein when the gain control signal is smaller than a gain threshold signal, the selector outputs the segment tuning control signal for controlling the IF amplifier to amplify the IF signal, and when the gain control signal is larger than the gain threshold signal, the selector outputs the gain control signal for controlling the IF amplifier to amplify the IF signal.