信号的时频分析-1.ppt

“Biomedical Signal Processing”Time-Frequency Analysis 2011.4.26 Contents（8 units） Introduction (2 units) Short-time Fourier Transform and applications (2 units)； Wavelet Transform and applications (2 units)； Seminar (2 units). Fourier analysis Gabor Transform (GT) f(t) ? L2(R), Gauss window function Window Wigner distribution function (WDF) There are many different kinds of definitions for the Wigner distribution function. The definition given here is special for time frequency analysis. Steps of time-frequency analysis Estimate the stationary of signal Decompose the signal Observe the time-frequency results Recover signal or model the signal Example (III) (Top) Time-frequency plot of mean power modulation time-locked to the theta trough. Outermost contour indicates statistical significance (P 0.001, corrected). Normalization permits comparison across frequencies; red and blue indicate a power increase or decrease, respectively, relative to the mean power. (Bottom) Theta trough–locked average of raw ECoG signal. Example (III) The modulation index as a function of analytic amplitude (5 to 200 Hz) and analytic phase (2 to 20 Hz) for the same electrode. Outermost contour indicates statistical significance (P 0.001, corrected). Larger values indicate stronger cross-frequency coupling. Maximal coupling for this electrode is 146.2 Hz amplitude and 5.6 Hz phase. * * * (1) Finding Instantaneous Frequency (2) Signal Decomposition (3) Filter Design (4) Sampling Theory (5) Modulation and Multiplexing (6) Electromagnetic Wave Propagation (7) Optics (8) Radar System Analysis (9) Random Process Analysis (10) Signal Identification (11) Acoustics 声学 (12) Biomedical Engineering (13) Spread Spectrum Analysis (14) System Modeling (15) Image Processing (16) Economic Data Analysis (17) Signal Representation (18) Data Compression (19) Seismology 地震学 (20) Geology 地质学 Applications of Time–Frequency Analysis Introduction Signa