A fragmentation channelizer has a transmitter channelizing filter bank that fragments a continuous spectral span of a signal input into discrete spectral channels. The discrete spectral channels coincide with available bandwidth segments of a communications channel. A receiver has a receiver filter bank that inputs the discrete spectral channels after transmission over the communications channel and de-fragments the discrete spectral channels into a reconstructed continuous spectral span of the signal input so as to generate a signal output corresponding to the signal input.