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Homework Help: Signal average power (complex signal)

  1. Mar 20, 2009 #1
    1. The problem statement, all variables and given/known data

    Evaluate the average signal power of the complex signal x(t) = e ^ jwt

    2. Relevant equations

    3. The attempt at a solution

    I know how to solve this but I have a couple of questions on why we have the take the magnitude of the complex signal in the integral? Besides, does a complex signal mean anything in reality? because the way I figured it is complex analysis is just a mathematical tool to help us analyse sinusoidal signals and a signal is always a real or an imaginery part of a complex function (e ^ jwt) and cant be both.

    And as such I tried evaluating the integral of e ^ jwt from 0 to To using two ways:

    1. write the exponential e ^ jwt in terms of cos and j sin then square that to give cos^2 wt +j2cos (wt) sin (wt) - sin^2 wt where it evaluates to some finite value
    2. square the funciton so it becomes e ^ j 2wt and write that in terms of cos and j sin where it evaluates to 0

    this is too mathematical I know, but how come the two mathematically valid manipulations yield integrals with different values?
  2. jcsd
  3. Mar 21, 2009 #2
    y am i being ignored?
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