Patent ID: 8890619

Claim:
A communication device comprising: a transmitter configured to receive an input signal and output a radio frequency transmit signal that is transmitted by the communication device; a main receiver configured to receive a radio frequency receive signal and output a main receiver output signal, the main receiver output signal comprising passive intermodulation distortion that is a non-linear function of the radio frequency transmit signal output by the transmitter; a tunable non-linear circuit configured to generate an intermodulation product signal comprising a plurality of intermodulation products as a function of a signal that is indicative of the radio frequency transmit signal; an auxiliary receiver configured to receive the intermodulation product signal to provide an auxiliary receiver output signal comprising only a subset of the plurality of intermodulation products that fall within a passband of the main receiver; an adaptive filter configured to adaptively filter the auxiliary receiver output signal to provide a passive intermodulation estimate signal that is an estimate of the passive intermodulation distortion in the main receiver output signal; and subtraction circuitry configured to subtract the passive intermodulation estimate signal from the main receiver output signal to thereby provide a compensated output signal.