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double side band modulation

Discussion in 'Homework Help' started by amangupta1219, Nov 11, 2012.

  1. amangupta1219

    Thread Starter New Member

    Oct 18, 2012
    the 2 signals shown are used for modulating ( DSB-SC) a carrier with frequency fc.
    Now i need to find the similarities and differences between their time domain representation.
    Clearly the both will have same envelope. Now i tried for the difference part but could not find it. One possibility according to me can be the phase change at t=1. Can we find that what will be the phase change for both modulated signals at t =1 without drawing the actual plot ?
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    Last edited by a moderator: Nov 11, 2012
  2. vk6zgo

    Active Member

    Jul 21, 2012
    As far as the modulator is concerned,the fundamental frequency of waveform(b) is double that of waveform (a).

    The modulator probably does not care if the negative 1/2 cycles of (b) go to zero volts rather than negative,all it sees is an increase in frequency, & a decrease in amplitude.

    Yes the envelope shape will be the same.