An introduction to time-frequency methods applied to biomedical signals

Time-frequency analysis preserves time and frequency information for non-stationary signals. The Wigner-Ville, Choi-Williams and Cone Shaped distributions (all part of Cohen´s class) all produce `cross-product´ terms which are not in the original signal. The Gabor spectrogram also suffers increasingly from spurious terms as its integer order parameter, D, increases. Only the short-time Fourier transform (STFT), and the adaptive algorithm don´t suffer from cross products. The STFT is by far the quickest to compute but has the poorest time-frequency resolution of all the above joint time frequency analysis techniques. It is concluded that S. Qian and D. Chen´s “Joint Time-Frequency Analysis-Methods and Applications” (Pub. Prentice- Hall, 1996) is an excellent introduction to the subject and to its applications