An adaptive feedforward equalizer (12) has switched (N - 1) tap-gain coefficients and a fixed tap-gain coefficient for the reference delay-line tap to operate on an incoming IF or baseband signal according to a first error signal ( epsilon 1) representative of the difference between the input and output of a decision circuit (15). All tap-gain coefficients are active in the absence of an interference from an undesired source to cancel precursor distortion. The (N - 1) tap-gain coefficients are nullified when such an interference is detected to reduce its precursor-cancelling capability. A first feedback equalizer (17) operates on the output of the decision circuit according to the first error signal to cancel postcursor distortion. A second feedback equalizer (18) nonlinearly filters the output of the decision circuit according to a second error signal ( epsilon 2) and generates an estimate of a desired component of the output of the feedforward equalizer. The outputs of the second feedback equalizer (18) and the feedforward equalizer (12) are combined to produce the second error signal, or an estimate of an undesired component of the output of the feedforward equalizer. In the presence of the interference, the desired component estimate ( epsilon 2) is combined with the outputs of the feedforward equalizer (12) and the first feedback equalizer (17) to produce an equalized signal for coupling to the decision circuit. <IMAGE>
Interference canceller with feedforward transversal filter having switched tap-gain coefficients