Aliasing avoidance and reduction of computational complexity in Volterra filters

Since a speaker system has nonlinearity, it is necessary to place a nonlinear inverse system in front of the speaker system so that the nonlinear distortion is corrected. However, in realization with DSP, the amount of computation in the Volterra filter used in the nonlinear inverse system is enormous. There exists a region containing aliasing components in the output signal of the Volterra filter. There is a way to band-limit the input signal in order to avoid aliasing. However, since the sampling frequency is set to twice the Nyquist frequency, an unnecessary band is processed and the efficiency is poor. Hence, in this paper, a configuration is proposed that does not cause aliasing even if the sampling frequency is chosen as the Nyquist frequency in order to reduce the amount of computation in the Volterra filter. Next, an identification method for the speaker system in order to efficiently obtain the Volterra filter used in the proposed configuration is presented. The proposed configuration is applied to the nonlinear inverse system. Finally, the effectiveness of the present method is demonstrated by simulation. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(1): 19–26, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10031