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Unformatted text preview: gnals Bandlimited Discretetime
BandDiscreteSignals • Since the spectrum of a discretetime signal
is a periodic function of ω with a period 2π,
a fullband signal has a spectrum occupying
the frequency range − π ≤ ω ≤ π
• A bandlimited discretetime signal has a
spectrum that is limited to a portion of the
frequency range − π ≤ ω ≤ π • An ideal bandlimited signal has a spectrum
that is zero outside a frequency range
0 < ωa ≤ ω ≤ ωb < π, that is
⎧0, 0 ≤ ω < ωa
X ( e jω ) = ⎨
⎩0, ωb < ω < π 7 • An ideal bandlimited discretetime signal
cannot be generated in practice
8 Copyright © 2005, S. K. Mitra Copyright © 2005, S. K. Mitra Bandlimited Discretetime
BandDiscreteSignals Bandlimited Discretetime
BandDiscreteSignals • A classification of a bandlimited discretetime signal is based on the frequency range
where most of the signal’s energy is
concentrated
• A lowpass discretetime real signal has a
spectrum occupying the frequency range
0 < ω ≤ ω p < π and ha...
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This document was uploaded on 11/09/2013.
 Fall '13

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