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Biomedical Signal and Image Processing
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Time signal
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Time

FIGURE 2.10 Signal x defined in the time domain.
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Frequency

Magnitude of DFT
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FIGURE 2.11 Magnitude of DFT of signal x.
magnitude of complex variables. The following code generates the graph shown in
Figure 2.11, which represents the magnitude of the DFT of the signal x:
y = fft(x);

y_magnitude = abs(y);

n = length(y_magnitude);

plot(y_magnitude(1:n/2−1) );

xlabel(‘Frequency’);

ylabel(‘Magnitude of DFT’);