Multiproduct Uniform Polar Quantizer

The aim of this paper is to reduce the complexity of the unrestricted uniform polar quantizer (UUPQ), keeping its high performances. To achieve this, in this paper we propose the multiproduct uniform polar quantizer (MUPQ), where several consecutive magnitude levels are joined in segments and within each segment the uniform product quantization is performed (i.e. all levels within one segments have the same number of phase levels). MUPQ is much simpler for realization than UUPQ, but it achieves similar performances as UUPQ. Since MUPQ has low complexity and achieves much better performances than the scalar uniform quantizer, it can be widely used instead of scalar uniform quantizers to improve performances, for any signal with the Gaussian distribution

Semilogarithmic Nonuniform Vector Quantization of Two-Dimensional Laplacean Source for Small Variance Dynamics

In this paper high dynamic range nonuniform two-dimensional vector quantization model for Laplacean source was provided. Semilogarithmic A-law compression characteristic was used as radial scalar compression characteristic of two-dimensional vector quantization. Optimal number value of concentric quantization domains (amplitude levels) is expressed in the function of parameter A. Exact distortion analysis with obtained closed form expressions is provided. It has been shown that proposed model provides high SQNR values in wide range of variances, and overachieves quality obtained by scalar A-law quantization at same bit rate, so it can be used in various switching and adaptation implementations for realization of high quality signal compression

Asymptotic Analysis of Optimal Piecewise Uniform Polar Quantization

In this paper, a simple and complete asymptotical analysis is given for a mean square error (MSE) piecewise uniform polar quantizer (PUPQ). We show that PUPQ has the same performance as the asymptotic nonuniform polar quantizer (NPQ) and has implementation complexity between complexities of NPQ and uniform polar quantization. The goal of this paper is solving the quantization problem in case of PUPQ and finding the corresponding support region

Piecewise uniform switched vector quantization of the memoryless two-dimensional Laplace source

A simple and complete asymptotical analysis of an optimal piecewise uniform quantization of two-dimensional memoryless Laplacian source with the respect to distortion (D) i.e. the mean-square error (MSE) is presented. Piecewise uniform quantization consists of L different uniform vector quan-tizers. Uniform quantizer optimality conditions and all main equations for optimal number of output points and levels for each partition are presented (using rectangular cells). The optimal granular distortion (i) for each partition in a closed form is derived. Switched quantization is used in order to give higher quality by increasing signal-to-quantization noise ratio (SQNR) in a wide range of signal volumes (variances) or to decrease necessary sample rate

Log-Polar Quantizer with the Embedded G.711 Codec

In this paper a new two-dimensional vector quantizer for memoryless Gaussian source, realized in polar coordinates, is proposed. The G.711 codec is embedded in our vector quantizer, and therefore our vector quantizer is compatible with the G.711 codec. It is simple for realization and it has much better performances, compared to the G.711 codec, such as much higher SQNR (signal-to-quantization noise ratio) for the same bit-rate, or bit-rate decrease for the same SQNR. The G.711 codec is widely used in many systems, especially in PSTN (public switched telephone network). Due to compatibility with the G.711 standard, our vector quantizer can be realized with simple software modification of the existing the G.711 codec, and therefore it can be very easily implemented in PSTN and other systems. So, small investments are needed for wide implementation of our model, but significant improvement of performances can be obtained

Analysis of compressor functions for Laplacian source’s scalar compandоr construction

А simple and complete analysis of nonuniform scalar quantizers based on the companding technique, so-called compandors, is presented. The performance of the scalar compandors for different definition of compressor functions are considered and compared with the performance of optimal Lloyd-Max’s scalar quantizers. There are several definitions of compressor functions. Two of them, that are functions of the support region of the compandor, are presented in this paper. The support region of the compandor is defined with the maximum amplitude of the input signal that enables optimal compandor’s load. In order to design the scalar compandor having the best performances i.e. with the smallest distortion, it is necessary to determine optimally its support region.Представлено простий і повний аналіз скалярних квантувателів зі змінним кроком, що базується на засобах компандування, так званих компандерах. Розглянуто характеристики скалярних компандерів при різних визначеннях функцій стиснення й наведено порівняння з характеристиками оптимальних скалярних квантувателів Ллойда-Мекса. Існує кілька визначень функції стиснення. Представлено два з них, які є функціями області підтримки компандера. Область підтримки компандера визначено максимальною амплітудою вхідного сигналу, що дає можливість оптимального завантаження компандера. Для розробки скалярного компандера з оптимальними характеристиками, тобто з найменшим викривленням, необхідно оптимально визначити його область підтримки.Представлен простой и полный анализ скалярных квантователей с переменным шагом, базирующийся на средствах компандирования, так называемых компандерах. Рассмотрены характеристики скалярных компандеров при различных определениях функций сжатия и приведены сравнения с характеристиками оптимальных скалярных квантователей Ллойда–Мэкса. Существует несколько определений функции сжатия. Представлены два из них, которые являются функциями области поддержки компандера. Область поддержки компандера определена максимальной амплитудой входного сигнала, что дает возможность оптимальной загрузки компандера. Для разработки скалярного компандера с оптимальными характеристиками, то есть с наименьшим искажением, необходимо оптимально определить его область поддержки

First Results of ATLASPix 3.1 Testbeam

The ATLASPix sensor has been developed as a monolithic High Voltage CMOS sensor candidate for the ATLAS inner tracker upgrade. The ATLASPix3 is the third version, and is the first full reticle-sized sensor developed for multi-module compatibility. The detector is operational, and has been tested as a single chip, and as a 4-layer telescopes in an electron testbeam, with energies up to 6 GeV at DESY. First results of the testbeam data analysis are presented here