Quotient Signal Decomposition and Order Estimation
Technical research rept.
MARYLAND UNIV COLLEGE PARK INST FOR SYSTEMS RESEARCH
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In this paper, the authors propose a method for blind signal decomposition of speech signals that does not require that the sources are independent or stationary. This method, which they consider a simple instance of nonlinear projection pursuit, is based on the possibility of recovering the areas in the time-frequency domain where the original signals are isolated, or almost isolated, with the use of suitable quotients of linear combinations of the spectrograms of the mixtures. The authors then threshold such quotients according to the value of their imaginary parts to prove that the method is theoretically sound under mild assumptions on the mixing matrix and the sources. They study one basic algorithm based on this method. The algorithm has the important feature of estimating the number of sources with two measurements. It then requires n-2 additional measurements to provide a reconstruction of n sources. Experimental results show that the method works even when several shifted versions of the same source are mixed.
- Radiofrequency Wave Propagation
- Voice Communications