Blind sources separation, independent component analysis (ICA) and related methods are promising approaches for analysis of biomedical signals, especially for EEG/MEG and fMRI data. However, most of the methods extract all sources simultaneously, so it is time consuming and not reliable especially, when the number of sensors is large (more than 100 sensors) and signals are contaminated by huge noise. The main objective of this paper is to present a new method for extraction of specific source signals using bandpass filters approach. Such a method allows us to extract source signals with specific stochastic properties, e.g., extraction of narrow band sources with specific frequency bandwidth.