Given a time series of possibly multicomponent input data, the method and apparatus includes a device that finds a time series of “source” components, which are possibly nonlinear combinations of the input data components and which can be partitioned into groups that are statistically independent of one another. These groups of source components are statistically independent in the sense that the phase space density function of the source time series is approximately equal to the product of density functions, each of which is a function of the components (and their time derivatives) in one of the groups. In a specific embodiment, an unknown mixture of data from multiple independent source systems (e.g., a transmitter of interest and noise producing system) is processed to extract information about at least one source system (e.g., the transmitter of interest).