Effects of Band Limiting on the Detection of Binary Signals

PCM/NRZ systems operating in the presenceof noise and in a band-limited channel areconsidered. Two types of bit detectors arestudied, integrate and dump, and sample. Theincreased signal power needed to give thesame performance as an optimum detectorand a broad-band channel is computed. Theresults depend on the bit pattern. The averageeffect of band-limiting over all bit patternsand two extreme cases are plotted for eachdetector. The results show that integrate anddump is always superior to sample and that ifthe sample detector is used, one should bandlimit before sampling at a frequency of 0.6times the bit rate.