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BIBO stability question

  1. Jan 28, 2012 #1
    Hi,

    I am trying to find out if a system is bounded (stable) or not, and I don't understand the process, I basically have these two functions,

    y1[n]=n2*x[n]

    y2[n]=x4[n]

    According to my notes, y1[n] is not stable, as the output is proportional to n2 which is not bounded, I understand this part. My notes also state that y2[n] is stable, this is what I don't understand, you have the input to the power of 4, why is this not-bounded ? Thanks in advance for any help
     
  2. jcsd
  3. Jan 29, 2012 #2
    A bounded quantity raised to the power of 4 would also be bounded. To me it is obvious why.

    A < x[n] < B

    A4 < (x[n])4 < B4
     
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