On the use of decorrelation in scalar signal separation

In this paper we describe a method to separate a scalar mixture of two signals. The method is based on the use of decorrelation as a signal separation criterion. It is proven analytically that decorrelating the output signals at different time lags is sufficient provided that the normalised autocorrelation functions of the source signals are sufficiently distinct. The method involves an iterative least-squares solution of a set of nonlinear equations. Alternatively, a gradient search algorithm can also be used to find the minimum of the sum of squares of these equations. Both time- and frequency-domain formulations are given. Some convergence and stability issues are discussed and a small example is given at the end