1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Signal Modulation

  1. Oct 16, 2004 #1
    How come a signal modulated using Amplitud Shift Keying and/or Phase Shift Keying (such as QAM) require a bandwidth? I mean, since the frequence is constant; only the amplitude and phase is changed.

    Thanks in advance!
  2. jcsd
  3. Oct 16, 2004 #2


    User Avatar
    Science Advisor
    Homework Helper

    It is not constant! The slope dV/dT changes from that of the unmodulated sine wave. This means that for a small periods of time it is different frequencies.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook