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Time scaing in discrete time variable?

  1. Sep 2, 2007 #1
    I wanted to know , if x(n) has DTFT X(e^jw)
    then can we define Y(e^jw) in terms of X(e^jw)?
    where Y(e^jw)is DTFT of y(n)=x(a*n)or y(n)=x(n/a)
    . Because in these cases terms of x(n) are either missed or '0' is padded up, so i think it won't be possible to define Y(e^jw) in terms of X(e^jw). can anybody tell i m right or not?
  2. jcsd
  3. Sep 3, 2007 #2

    OK, i got the answer for y(n)=x(a*n), where a is an integer. Y(e^j[tex]\omega[/tex]) can be defined.

    it is (1/a)*[tex]\sum[/tex]X(exp(j([tex]\omega[/tex]+2[tex]\pi[/tex]m)/a)) where m varies from 0 to a-1.

    But can anybody plz tell; is it possible for y(n)=x(n/a) to define Y(e^j[tex]\omega[/tex]). i am getting confused becoz of 0's which come in y(n) in this case.
    Last edited: Sep 3, 2007
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