Optimum design of vector-quantzed subband codecs

Abstract

This correspondence provides an approach for representing an optimum vector quantizer by a scalar nonlinear gain-plus-additive noise model. The validity and accuracy of this analytic model is confirmed by comparing the calculated model quantization errors with actual simulation of the optimum Linde-Buzo-Gray (LBG) vector quantizer. Using this model, we form MSE measure of an M-band filter bank codec in terms of the equivalent scalar quantization model and find the optimum FIR filter coefficients for each channel in the M-band structure for a given bit rate, given filter length, and given input signal correlation model. Specific design examples are worked out for four-tap filters in the two-band paraunitary case. These theoretical results are confirmed by extensive Monte Carlo simulation. © 1998 IEEE.