https://rep.bntu.by/handle/data/68585 2026-04-21T12:52:40Z 2026-04-21T12:52:40Z Тимофеев, А. М. https://rep.bntu.by/handle/data/68593 2020-03-18T00:16:07Z 2020-01-01T00:00:00Z

Методика снижения потерь информации в асинхронном двоичном однофотонном канале связи с приёмником на основе счётчика фотонов Тимофеев, А. М. Приёмные модули однофотонных систем связи при измерении маломощных оптических сигналов должны обеспечивать наименьшие потери передаваемой информации. В этой связи целесообразно использовать счётчики фотонов, которые являются высокочувствительными, однако характеризуются ошибками регистрации данных. Цель работы – разработать методику определения интенсивности регистрируемого оптического излучения в канале однофотонной связи с приёмным модулем на основе счётчика фотонов, позволяющую уменьшить вероятность ошибочной регистрации передаваемых двоичных символов. Разработаны методика снижения потерь информации в асинхронном двоичном однофотонном канале связи с приёмником на основе счётчика фотонов и устройство, её реализующее. Данная методика основана на использовании статистических распределений смеси числа темновых и сигнальных импульсов, полученных на выходе счётчика фотонов при регистрации двоичных символов «0» Pst 0 (N) и «1» Pst 1 (N). Сущность методики заключается в определении интенсивностей оптических сигналов для передачи двоичных символов («0» и «1») и пороговых уровней N1 и N2 импульсов, зарегистрированных на выходе счетчика фотонов. Обоснован выбор параметра в качестве критерия для реализации методики. Методика позволяет определить нижний и верхний пороговые уровни зарегистрированных импульсов, а также интенсивности оптических сигналов при передаче двоичных символов, обеспечивающие уменьшение вероятности ошибочной регистрации двоичных данных.

2020-01-01T00:00:00Z Serenkov, P. S. Hurevich, V. L. Tolochko, T. K. https://rep.bntu.by/handle/data/68592 2024-09-23T09:43:46Z 2020-01-01T00:00:00Z

Features of Аpplication of a Сombined Аpproach to the Еvaluation of the Мeasurement Results Uncertainty Serenkov, P. S.; Hurevich, V. L.; Tolochko, T. K. The article exposes description of features of the combined approach application to the evaluation of measurement results uncertainty. The aim of this work is the justification and development of new science-driven approaches to achieve maximum efficacy of measurements on the criteria "accuracy/costs" at the stated level of confidence. It provides theoretical base for correctness of combined approach to assess measurement results uncertainty. There is proposition to conventionally divide measurement process into fragments – combining objects, each from shall be considered as individual element for evaluation. It is well known that combining objects can be formed by grouping individual components (resources) of the measurement process either via separate stages of the measurement process. Correctness of such approach is based on the application of "resource" and "process" approaches as regards identification of the factors that affect the measurement results uncertainty. This article provides recommendations on selection of model or empiric approach for evaluating of particular contributions from combining objects of different types into total uncertainty of the final measurement result. In order to improve the validity of empiric approach of the criteria of sufficiency of measurement method uncertainty examination was formulated. It is recommended to evaluate the total uncertainty of the final measurement result by complexation of evaluations of particular total uncertainty of the results for all fragments according to the uncertainties distribution law. It is determined two typical cases of effective application of the combined approach to evaluation of measurement results uncertainty: method of direct measurements and method of indirect measurements. This article considers features of effective application of the combined approach for both situations providing corresponding examples. Special attention is paid to the application of the combined approach to assessing the test results uncertainty. As distinct from the measurement process realized under normal conditions, testing process includes additional external influence factors that are determined by test conditions.

2020-01-01T00:00:00Z Majewski, J. https://rep.bntu.by/handle/data/68591 2020-03-18T00:15:55Z 2020-01-01T00:00:00Z

The Dynamic Behaviour of Capacitive Humidity Sensors Majewski, J. The sensor design features and the sensing material properties which can influence the response time of the polymer-based capacitive humidity sensors are shortly discussed. The ways of specifying the dynamic properties of capacitive humidity sensors in technical data sheets by the leading companies on the market are briefly characterized and discussed. The schematic view and operation of the experimental setup for determining of the dynamic parameters of capacitive humidity sensors at different temperatures of humid air are described. The dynamic behaviour of polymer-based capacitive humidity sensors was registered as the measurement profiles for both positive and negative step changes in humidity level. The response and recovery times, as well as the time constants for the exponential approximation fits of the step responses, were determined either graphically or analytically, based on the collected data. The changes of these parameters under atmospheric pressure within the temperature range from – 30 °C to + 20 °C were analysed. The exemplary transient measurement profiles are shown, together with the illustrations of the graphical method for determining the response and recovery times. Also, the plots of the relationship between response and recovery times as well as time constants, and temperature, are presented. Some explanations of the obtained results are suggested.

2020-01-01T00:00:00Z Turek, M. Wegierek, P. https://rep.bntu.by/handle/data/68590 2020-03-18T00:15:56Z 2020-01-01T00:00:00Z

Negative Ion Beam Emittance Calculations Turek, M.; Wegierek, P. Computer simulations are commonly used to support design and optimisation of powerful negative ion sources for the needs of future thermonuclear reactors like e. g. ITER. The aim of the paper was to study changes of produced beam quality (described by its emittance and brightness) with the geometry of the extraction system as well as extraction voltage. A two-dimensional Particle-in-Cell (PIC) method based code was applied to model H- ions and electrons extraction from the ion source plasma chamber through the opening with bevelled surface. The root-meansquare emittance of the extracted beam was calculated according to Chasman and Lapostolle approach. Ion beam phase space portraits were also presented to enrich the discussion. Growth of ion (electron) beam emittance was observed both with the increasing radius of the extraction opening and the inclination of its bevelled surfaces. This degradation of beam quality is partially balanced by increasing extracted H- ion current. On the other hand, increasing length of the extraction channel improves the beam quality. It was demonstrated that for wider extraction opening the H- ion beam consist of two parts coming form the two different regions of the chamber. According to calculated beam brightness the optimal wall inclination was found to be near 26o in the studied case. The decrease of the beam emittance saturates for larger channel length values. In the considered case the optimal channel length was h = 1.7 mm. The evolution of ion beam emittance and brightness shows that the best beam quality is achieved for extraction voltages between 0.5 kV and 2 kV.

2020-01-01T00:00:00Z