Q1 — Communications

Q1

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Given an AM system with modulation index µ = 1 (or 100% modulation) and modulation voltage

v(t)=K[2 cosωmt+4 cos2ωmt+2 cos3ωmt]v(t)=K[2cosωmt+4cos2ωmt+2cos3ωmt]

Assume ωc=2πfc=10ωm.ωc=2πfc=10ωm.

A normalized signal, x(t), is a scaled sum of three cosine terms, as shown. The signal is amplitude-modulated by a system having a modulation index of 1.0.

x(t)=K(2 cosωmt+4 cos2ωmt+2 cos3ωmt)

Most nearly, what value of K is required to obtain a normalized signal?