Patent ID: 8223900

Claim:
A receiver with automatic gain control comprising: a) a receiver stage having a modulated signal input, a signal output, an Automatic Gain Control (AGC) input and an AGC output, whereby a signal at said signal output experiences a gain from said receiver stage; b) a matched AGC stage including: i) control circuit including an AGC Digital-to-Analog Converter (DAC) having a digital input and an analog output and a Low Noise Amplifier (LNA) gain controller having an input coupled to said analog output of said AGC DAC and an output coupled to said AGC input of said receiver stage; and ii) a feedback circuit comprising a peak detector having an input coupled to said AGC output and an output, and a Received Signal Strength Indication (RSSI) Analog-to-Digital Converter (ADC) having an input coupled to said output of said peak detector and a digital output defining a waveform, whereby said control circuit and said feedback circuit have matched transfer characteristics; and c) a digital processor having a waveform input coupled to said digital output of said RSSI ADC and an control output coupled to said digital input of said AGC DAC, said digital processor being operative to develop a gain control signal at said control output to set a desired gain level of said receiver stage to an optimal level based upon a waveform analysis derived from said gain feedback signal; wherein said receiver stage includes a variable gain preamplifier circuit having, as inputs said modulated signal input and said AGC input, an intermediate frequency circuit having an input coupled to an output of said preamplifier circuit, it detector circuit having an input coupled to an output of said intermediate frequency circuit, and a rectification circuit having an input coupled to an output of said detector circuit.