Abstract: In 1998 , Torkkola gave information maximization rules of a feedback architecture which can only separate minimum phase mixtures,though working well on simulated data,they fail in real environment which usually involve non-minimum phase transfer systems. This paper analyses the rules of the feedback architecture and presents an informax maxization algorithm of a feedforward architecture in the frequency domain which corresponds to a non-causal FIR.The new algorithm can solve the non-minimum phase mixing problem well.At last, simulation experiments will prove that two natural signals in a real environment can be separated successfully. Keywords: blind source separation(BSS); information maximization; convolved mixtures; natural gradient