Biomedical Engineering Reference
In-Depth Information
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4
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Time (sec)
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(a)
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(b)
Frequency (Hz)
FIGURE 11.13
(a) 100 Hz sine wave corrupted with noise. (b) Fast Fourier transform (FFT) of noisy 100 Hz sine
wave.
of frequency of 100 Hz. Figure 11.12b shows the FFT of the 100 Hz sine wave. Notice that
the peak of the FFT occurs at 100 Hz frequency, indicating that all of the energy is confined
to this frequency. Figure 11.13a shows a 100 Hz sine wave corrupted with random
noise that was added to the waveform. The frequency of the signal is not distinct in
the time domain. After transforming this signal to the frequency domain, the signal
(Figure 11.13b) reveals a definite component at 100 Hz frequency, which is marked by the
large peak in the FFT.
