Filter example: noisy sinusoid

Noisy, discrete-time waveform 

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Discrete spectrum: Fast Fourier Transform (FFT) 

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Filter (DC to 15Hz)

Define filter 
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Low-pass filtered signal 
[Graphics:../Images/index_gr_36.gif]

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Filter (15Hz to 500Hz)

Define filter 
[Graphics:../Images/index_gr_38.gif]

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High-pass filtered signal 
[Graphics:../Images/index_gr_40.gif]

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Converted by Mathematica      January 13, 2003