A method of ameliorating channel effects present in a signal received through a channel, wherein the signal conveys at least first and second information streams and the method comprises the steps of determining from the first stream activation of the second stream and processing the signal to ameliorate channel effects, when the second stream is present, in a first manner comprising filtering the signal through filter means to ameliorate channel dispersion and then processing the signal through Rake receiver means or, when the second stream is absent, in a second manner comprising processing the signal through the Rake receiver means without prior amelioration of channel dispersion by the filter means.