Virtual measurement system for UHF-transistor amplifiers

• Main Author: Alexander D. Tupitsyn
• Format: Article
• Language: Russian
• Published: Saint Petersburg Electrotechnical University "LETI" 2020-01-01
• Series: Известия высших учебных заведений России: Радиоэлектроника
• Subjects: simulation modeling; small signal amplifier; uhf-amplifier s-parameters measurement; virtual measurement system; multiport devices; scattering and transfer matrixes; labview virtual devices
• Online Access: https://re.eltech.ru/jour/article/view/386

Introduction. Measurement systems for research of telecommunication devices and of their elements are difficult to maintain and expensive. Therefore when possible, its may be replaced by virtual measurement systems (VMS), which allow one to perform measurements based on physical parameters of testing device.Aim. VMS development for measuring of amplifiers parameters by means of simulation modeling based on amplifier topology.Methods and materials. VMS is to be used for research of a small signal amplifier (a part of transceiver). It consists of program modules and graphic interface, realized by LabVIEW. The program part contains text modules in LabVIEW syntax, which calculate S-parameters frequency dependencies for an amplifier. For definition of parameters amplifier circuit by a decomposition technique is being split into sequential two-port net-works, which can be described by corresponding matrixes. After determination of frequency dependent matrixes elements, the matrixes are being converted and multiplied. It allows one to obtain frequency dependencies of parameters of an amplifier. VMS interface is a 3-D-rendered on a computer screen front panel of a virtual vector network analyzer with a device under test connected to its test ports.Results. VMS for UHF-amplifiers research based on given topology was described. The calculations of amplifier transmission lines and amplifier in the whole parameters based on corresponding matrixes and their conversions were presented. The algorithm of a measuring system operation was described. 3D measuring complex and objects under test visualization were shown. The comparison with existing software for design and simulation of UHF-devices such as Microwave Office was realized.Conclusions. Contrary to Microwave Office, aimed to solution of synthesis tasks, VMS is aimed to research tasks. It has a realistic visualization of measurement devises and simple parameters input, do not need big computer resources and is free. VMS can be used in educational process, especially for online education, when using of Microwave Office is impossible.