Model-based filter banks and corresponding subband coding systems: Multirate state-space approach

Abstract

A new model-based filter bank configuration is proposed in this work and its corresponding subband coding schemes are also discussed. The proposed filter bank system is developed specifically for the autoregressive input signals with a consideration of subband noises. First, the analysis filters are designed on the basis of the conventional frequency splitting algorithms. Next, the synthesis filter is derived according to the composite effects of the AR input signal, the allpass analysis filters, and the white subband noises. State-space framework is used to describe the analysis section. Hence, a new multirate Kalman synthesis filter is derived to achieve optimal signal reconstruction. Computer simulations reveal that perfect reconstruction is achieved for the clean subband case and optimal reconstruction is obtained when the corrupting noises exist in the subband paths. In addition, the subband coding systems pertaining to the proposed model-based filter bank configuration have the advantage of better reconstructed speech quality and possess a flexible subband number and down-/up-sampling factor.