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Comprehensive explanation of Aliasing?

  1. May 16, 2007 #1

    I need a comrehensive explanation of Aliasing? and its relation to filters...

    Thanks for the answers
  2. jcsd
  3. May 16, 2007 #2
    start with wikipedia...
  4. May 16, 2007 #3


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    Staff: Mentor


    Aliasing is what happens when you take a continuous signal and digitize it. It can only be approximated and as a result, smooth lines in a signal (whether they are a synthesized sound wave or a picture or some other signal is irrelevant) become jagged.
  5. May 16, 2007 #4
    Aliasing is a form of distortion that happens when you sample a signal with a frequency less than the nyquist rate, the sampling theory simply states that if we take a number of samples of a signal at double the rate of it's highest frequency, the original signal can be reconstructed using these samples, so what happens when you sample at a rate lower than nyquist is that there will be an aliasing effect.

    The aliasing effect could be removed by passing the signal through a low pass filter before sampling, thus we could calculate the band of the filter and multiply it by two and then sample at this rate.
  6. May 16, 2007 #5
    Thanks a lot guys, I have already used wiki...Thanks again!

    I will post my summary in the coming days so we all benifit from it!
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