Модифікована структура дворівневого цифрового синтезатора частоти для дозиметрії

Abstract

Наведена модифікована структура дворівневого цифрового синтезатора частоти, що поєднує в собі властивості класичних дворівневих цифрових синтезаторів частоти і генераторів пуассонівських імпульсних послідовностей.Digital frequency synthesizers are widely used in various fields of technology. Their main advantages, compared to analog devices, are the accuracy of output signal, resistance to external factors, reliability and high performance. Their structures include the digital storage device (accumulative adder) and a comparison scheme. Basing the latest the two-level digital frequency synthesizers are developed. They are the subset of digital frequency synthesizers, in which the output signals are two-levelled. The papers show the improved structures of digital frequency synthesizers with the extended functional capabilities, in which the possibility of the step of the output frequency alteration is implemented. Poisson pulse sequence generators are used mainly to simulate various natural and technical processes that are subjects of the Poisson distribution law. They can be implemented basing on different structures. For instance, the basis of one of them is provided by a pseudorandom number generator and a comparison scheme. The similarity of the two-level digital frequency synthesizers and Poisson pulse sequence generators constructing principles allow conjugate them in one structure. Here, the extended possibilities for managing the output signal frequency are combined with its formation in accordance with the Poisson distribution law. Such a frequency synthesizer can be applied to simulate different processes. In particular, one application consists in simulation of the output signals of the dosimetric detectors. It is caused by active search of various types of extremist and terrorist organizations around the world and puts on the agenda an increased control over the movement of radioactive materials both internally and through borders of countries, including strengthening control over their movement through sea ports and airports. It produces the new requirements aiming the enhancement of the speed, accuracy, and reliability of dosimetric measurements.