Wideband 160-channel polyphase filter bank cable TV channeliser

The authors present a novel design of a wide bandwidth polyphase up-sampling filter bank formed by cascading external shaping filters, arbitrary interpolators and two stages of polyphase channelisation. The channeliser synthesises 160 channels with 6-MHz frequency centres and thus spans a two-sided baseband bandwidth of 960 MHz. The two stages of channelisation first form super channels from ten sets of 16-channels each in 32-path polyphase channelisers operating at an output sample rate of 192 MHz. These ten super channels are, in turn, channelised by a 16-path polyphase channeliser operating at an output sample rate of 1536 MHz. The two-stage approach permits the ten sets of first stage super channel channelisers to operate at an easy to implement medium sample rate. The complex baseband signal is further up-sampled 1-to-2 and translated to a digital intermediate frequency and pre-compensated for the sin(x)/x distortion of the output digitalto-analogue converter.