Analysis of nonminimum phase component on direct transfer function and its inverted transfer function

This paper presents analysis of nonminimum phase component on acoustic transfer function as unknown system when adaptive FIR (finite impulse response) filter is used for noise cancelling scheme. For the application in realistic reverberant environment, nonminimum phase component is analyzed in beamforming structure. From the analysis, it has been found that it provides a consistency in estimate by adaptive FIR filter between direct and its inverted transfer functions. Based on this, by applying minimum phase filter in front, it will be shown that rear-end adaptive FIR filter is only related with nonminimum phase term due to absorption of minimum phase term by front-end minimum phase filter in beamforming structure.