Abstract
The problem we address in this paper is the design of nearly optimal scalar quantizer in a wide variance range of the Laplacian input signals, using the piecewise uniform quantizers while restricting the class of quantizers to be forward adaptive. Particularly, the design procedure of the piecewise uniform quantizer with an equidistant support region partion and the optimized reproduction level distribution per segments is presented along with the design procedure of its forward adaptive version. Reproduction level optimization is performed by optimizing the granular distortion of the proposed quantizer using the method of the Lagrange multipliers. For the proposed model we study the influence of the segment number on the SQNR, as well as the SQNR robustness in a wide variance range. Since the results obtained for the assumed Laplacian distribution indicate the SQNR improvement over the G.711 standard, one can expect that the proposed quantizer will be effective in the quantization of signals having the same distribution and the time varying characteristics. Ill. 4, bibl. 10 (in English; abstracts in English and Lithuanian).DOI: http://dx.doi.org/10.5755/j01.eee.119.3.1356
Highlights
The primary goal of the quantizer design is to determine the reproduction levels and the partition regions or cells such as to provide the minimum possible distortion for a fixed number of quantization levels N, or equivalently a fixed resolution R=log2N [1, 3]
If a quantizer support region consists of several segments, each of which contains several quantization cells and reproduction levels corresponding to a uniform quantizer, the quantizer is a piecewise uniform one [1, 2]
The G.711 quantizers based on a piecewise uniform approximation to the A-law and μ-law compressor characteristics [1] divide the support region into a 2L=16 unequal segments, each of which has equal number of cells
Summary
The primary goal of the quantizer design is to determine the reproduction levels and the partition regions or cells such as to provide the minimum possible distortion for a fixed number of quantization levels N, or equivalently a fixed resolution R=log2N [1, 3]. In the reference [5], in the conclusion of the paper, the authors have highlighted that the main drawback of their method is that they do not have a manner for deciding how to determine the segments into which to divide the support region of a piecewise uniform quantizer for an arbitrary signal distribution. This comment has motivated us to propose an intuitively obtained solution, i.e. to research the performance of the PUSQ that defines the equidistant support region partion and the optimized distribution of the cells (or reproduction levels) within such defined segments. The considered PUSQ is completely specified and both the granular and the overload distortion can be determined along with the signal to quantization noise ratio [1, 2]
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