Analysis of Methods for Measuring Parameters of Weakly Polarized Low-Frequency Magnetic Fields
Students Name: Shelepeten Bohdan Vasylovych
Qualification Level: magister
Speciality: Radioelectronic devices, systems and complexes
Institute: Institute of Telecommunications, Radioelectronics and Electronic Engineering
Mode of Study: full
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: Shelepeten B.V., Prots R.-B.V. (supervisor). Analysis of Methods for Measuring Parameters of Weakly Polarized Low-Frequency Magnetic Fields. Master thesis. - Lviv Polytechnic National University, Lviv, 2020. Extended abstract The work is devoted to the research of methods for measuring weakly polarized magnetic fields, namely their use in defectoscopy, to search for metal objects at great depths, as well as in such sciences as hydrogeology, archeology and geophysics. As modern science and technology puts forward harsh reprimands for various technical means used in various sectors of the economy, improving the quality of products is given much attention and large funds in all industrialized countries. This paper will investigate the measurement errors of weakly polarized magnetic fields and propose ways to reduce them. This is necessary in order to maximize the accuracy of low-frequency electromagnetic measurements. The system of such measurements consists of receiving and transmitting elements that cooperate with each other. Improving the accuracy of the orientation of the receiving elements is associated with significant technical difficulties, especially when measuring the parameters of low-frequency fields, and always leads to the complexity of the measuring system, a sharp decrease in its speed and sensitivity. In the first section of the work the structure of the polarized electromagnetic field is considered. The alternating electromagnetic field and in the General case is elliptically polarized. This polarization occurs as a result of adding the primary field of the pathogen to the secondary field of eddy currents. It is this secondary field that will change over the defects in the test environment. Therefore, the parameters that characterize the electromagnetic field polarization ellipse reflect information about the physical properties and geometric dimensions of the conductive object. The second and third sections consider methods for measuring the parameters of the polarized field and their errors, respectively. The second section presents several schemes that can be used to measure the parameters of a polarized field, but each scheme has its advantages, disadvantages and errors. The errors described in the third section include the non-identity of the amplitude frequency characteristics of the paths, the non-identity of the phase-frequency characteristics of the paths, the inaccuracy of the quadrature phase shift and the errors of single-channel signal conversion. The fourth section covers the methods of construction of highly stable functional devices, namely the construction of broadband receivers, the study of phase shifting units. Also, the method of reducing errors in single-channel signal conversion is considered here. The object of research - methods for measuring the parameters of low-frequency weakly polarized magnetic fields. The subject of research - the magnetic field, devices for measuring its parameters, reducing measurement errors. The scope of the research - is the optimal choice of methods and algorithms for measuring the invariant characteristics of elliptical polarization. Goal of research: study of methods for measuring the characteristics of magnetic fields, study of errors of these characteristics, ways to reduce errors, consideration of the principles of construction of highly stable magnetic antennas, quadrature phase converters and phase-sensitive signal converters. Keywords: magnetic field, invariant characteristics, increasing the accuracy of measuring instruments, polarization, measurement methods. References: 1. Skripnik Yu.A. Improving the accuracy of measuring devices. "Technology", 1976. 2. Skripnik Yu.A. Methods of measuring transformations and structure of electronic devices. - "Measuring equipment", 1969, №4. 3. Equipment for aerogeophysical reconnaissance / Vakulsky AA et al .: Kiev: Nauk. opinion, 1985. 4. Bursian VR The theory of electromagnetic fields used in electrical exploration. Ed. LSU, L., 1936. 5. Nedostup LA, Kiselychnyk MD, Bobalo Yu.Ya. Fundamentals of reliability of electronic devices: Textbook. manual. - Lviv: Lviv Polytechnic State University Publishing House, 1998. - 219 pp., Ill.