Reconstruction of wideband signals from outputs of overlapped, delayed narrowband receivers

A signal whose bandwidth exceeds that of available receivers can be reconstructed from the outputs of spectrally overlapped receivers. Adaptive filters were used to compensate for varying amounts of overlap, relative delay between receiver outputs, and a small amount of frequency shift. The preferred architecture contains adaptive multiple transversal filters, each of which incorporates an adaptive lattice filter to prewhiten the data, thereby allowing faster convergence. Simulation results are provided in the case of quadriphase shift keyed (QPSK) quadrature amplitude modulated (QAM) signals with a 4*4 signal constellation (16-QAM), two receivers, and two adaptive filters. Results indicate that, for a wide range of overlaps and even when the relative delay between receiver outputs is several symbols, the equalizer structure will converge in roughly the same time as a conventional equalizer applied to an unfiltered signal. >