Date Added: Jul 2012
Base band transmission of digital data requires the use of a low pass channel with a bandwidth large enough to accommodate the essential frequency content of the data stream. However, the channel is dispersive in that its frequency response deviates from that of an ideal low pass filter. The result of data transmission over such channel is that each received pulse is affected somewhat by adjacent pulses, thereby giving rise to a common form of interference called ISI. To control ISI, control has to be exercised over the pulse shape in the overall system, known as pulse shaping.