| Summary: | 碩士 === 中正理工學院 === 電子工程研究所 === 85 === In order to study the process of the signals of carotid pressure before and after anesthesia, both fast Fourier transform (FFT) and wavelet transform are adopted in this thesis. Both methods are used to study the affection of signals variantion in the frequency domain. Also the merits and drawbacks of using these methods to analyze physiological signals are compared.
It is well-known that FFT and wavelet transform are widely used powerful tools in mathematical analyses and signal processing. FFT is a method that transforms a signal from time domain into spectrum domain while wavelet transform possesses the characteristics of multiresolution and multiscale. Thus, wavelet transform is considered suitable for analyzing non-stationary signals. However, the variation in signals of carotid pressure in frequency domain before and after anesthesia are low, we found that the wavelet transform are not very effective as compare to FFT in revealing the variation of signals.
Finally, to compute the power spectrum of signals as the result of FFT, and to analyze the spectrum which include three areas of 0-0.4 Hz, 0.4-0.6Hz and 0.8-1.8Hz. From the power spectrum diagram, we can find that the power would raise when the animal awake gradually from anesthesia. And the phenomenon may look on as an index which anesthetists observe the depth anesthesia.
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