Minimization of quantization noise amplification in 2-channel IIR bi-orthogonal filter bank

In this work we look at the class of uniform biorthogonal FIR, IIR and hybrid filter banks with M = 2 channels. When quantization noise passes through the synthesis filter bank, it gets amplified due to the multiplication of synthesis filter norms to the quantization noise in each channel. Better compression, or higher coding gain, can be achieved if the quantization noise amplification is reduced. Scaling down of the synthesis filters to maintain the property of perfect reconstruction does not work so the analysis of the filter bank needs to be scaled up. Minimization of such amplification has been proposed earlier for FIR filter banks. We are proposing an implementable and stable coloring filter for IIR filter bank which is the optimum coloring filter for the assumed filter structure. We deal with an example of a hybrid filter bank based on all pass delay chain structure.