Patent ID: 6959056

Claim:
Apparatus for cancelling radio frequency noise occurring in a communications channel, comprising input means ( 10 , 12 , 16 , 26 ) for connection to the communications channel ( 14 ) and for extracting therefrom a differential signal (S) and a common mode signal (CM), narrowband noise estimation means ( 28 ) responsive to the common mode signal (CM) for producing a first noise estimate signal (E A ) derived from relatively high amplitude narrowband radio frequency interference in one or more narrow frequency bands and wideband noise estimation means ( 30 ) responsive to the common mode signal for producing a second noise estimate signal (E D ) derived from relatively low amplitude wideband radio frequency interference in frequency bands other than said one or more narrow frequency bands, control means ( 60 ) for controlling gain and/or phase of the noise estimate signals in relation to the differential signal (S), means ( 48 ) for subtracting the first and second noise estimate signals from the differential signal, and means for compensating for phase differences between the common mode component in the differential signal and each of the first and second interference estimate signals before the signals are summed or added.