Also known as: pulse shaping

Pulse shaping is filtering each transmitted symbol’s pulse so the signal occupies less bandwidth and successive symbols don’t smear into one another (inter-symbol interference).¹ Sharp rectangular pulses spray energy into adjacent channels; a shaped pulse keeps it contained.

Shaping each symbol pulse (often with a root-raised-cosine filter) contains the signal's spectrum.

Overview

The most common choice is the root-raised-cosine filter, split between transmitter and receiver so that together they form a Nyquist filter with zero inter-symbol interference at the sampling instants.

Sources

1. Pulse shaping — Wikipedia, for the bandwidth-limiting and inter-symbol-interference rationale. ↩

See also

• Root-raised-cosine filter
• Bandwidth
• Symbol rate (baud)
• Matched filter

Learn it step by step

• Digital modulation & constellations