Patent ID: 7706769

Claim:
A method of reducing the effects of second order intermodulation distortion in a zero-IF receiver, comprising: receiving an RF signal, modulating and amplifying the RF signal to provide one or more baseband signals, then detecting an occurrence of intermodulation distortion within the one or more baseband signals, and selectively enabling a wide mode of a wide-notch filter having a predetermined wide mode and a normal mode, said wide mode having a wider frequency range than said normal mode for attenuating signal components of the one or more baseband signals within the predetermined wide mode frequency range of the wide-notch filter to reject the second order intermodulation distortion, wherein detecting the occurrence of intermodulation distortion comprises determining a plurality of signal strength measures, and determining the occurrence of intermodulation distortion based on a relationship among the plurality of signal strength measures, the plurality of signal strength measures comprising an RSSI measure and an Eb/Nt measure, and determining the occurrence of intermodulation distortion if: Eb/Nt<energy threshold; and RSSI<minimum signal strength; and maintaining the wide mode enablement of the filter while either a decrease in RSSI exceeds a predetermined decrease or an increase in the Eb/Nt ratio exceeds a predetermined normal Eb/Nt ratio.