kernel. In this way, time-frequency analysis based on the resulting complex-valued extension of the time-causal limit kernel makes it possible to capture essentially similar transformations of a temporal signal as the Gabor function can, and corresponding to the Heisenberg group, see for further details. See also Gabor filter Gabor wavelet Gabor atom Time-frequency representation S transform Short-time Fourier transform Wigner distribution function References D. Gabor, Theory of Communication, Part 1, J. Inst. of Elect. Eng. Part III, Radio and Communication, vol 93, p. 429 1946 (http://genesis.eecg.toronto.edu/gabor1946.pdf) Jian-Jiun Ding, Time frequency analysis and wavelet transform class note, the Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, 2007. Integral transforms