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7 - Spectrum of Digitally Modulated Signals

Published online by Cambridge University Press:  aN Invalid Date NaN

Tolga M. Duman
Tolga M. Duman
Affiliation:
Bilkent University, Ankara
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Summary

Digital transmission over bandlimited channels is studied. The concept of intersymbol interference (ISI) is described, and the Nyquist criterion for no ISI is derived. The raised cosine pulse, a widely used example of a practical communication pulse resulting in no ISI, is introduced. Both ideal and non-ideal bandlimited channels are considered. In addition, the power spectral density of digitally modulated signals is derived, and the spectral efficiencies of different digital modulation schemes are computed.

Keywords

Bandlimited channelsintersymbol interferenceNyquist rateNyquist criterion for no ISIpower spectral densityspectral efficiency
Type
Chapter
Information
Fundamentals of Digital Communication Systems , pp. 290 - 317
Publisher: Cambridge University Press
Print publication year: 2025

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