Patent ID: 7065335

Claim:
An automatic gain control (AGC) circuit comprising: a forward transmission path having, in use, applied at its input an input RF signal and to provide at its output an output signal; a variable gain AGC amplifier in the forward transmission path for processing the input RF signal, which amplifier has a control input and is responsive to a control signal applied at its control input to vary its gain; a feedback loop coupled from the output of said forward transmission path and to said control input of said AGC amplifier, said feedback loop including a signal detector that has a predetermined non-linear gain response, depending on an input signal level, the gain being higher for greater input signal strength; an integrator coupled to said control input of said amplifier; a voltage source coupled to said integrator and to said control input of said amplifier; and a further variable gain device for varying the gain or attenuation of a signal applied as an input signal to the control input of said AGC amplifier.