Measuring. Monitoring. Management. Control

Background. Increasing the performance of remotely controlled on-board equipment of autonomous information and measurement systems when entering flight task data into it requires the use of a clock frequency significantly higher than that required for autonomous operation of equipment selected based on the minimum current consumption. The task to eliminate this contradiction, complicated by the need to have information about the exact ratio of the used frequencies, is urgent. Materials and methods. The solution of the above problem can be realized by using digital frequency multipliers. Results. The variants of frequency multipliers construction are considered. It is shown that the known variants of multipliers construction cannot fully satisfy the necessary requirements. Multipliers using a pulse pack generator have a large unevenness of the output pulses, and multipliers using automatic frequency adjustment do not have instantaneous mode output, moreover, multipliers with automatic tuning and a frequency detector on a 512PS8VC chip can have a duration of transients exceeding several tens of seconds. A combined method of frequency multiplication is proposed. Conclusions. It is shown that the combined method of frequency multiplication based on generation of pulse packs and auto-tuning with phase detection combines positive qualities of pulse packs generation in the part of instantaneous output to the mode and small non-uniformity of output pulses of auto-tuning.

Background. The relevance of the topic is due to the necessity to develop a calibration procedure for pipeline inspection gauge magnetic sensor taking into account the possibility of automating the calibration process with softwareand hardware, since there is no suitable integrated solution due to the specifics of the sensors application. The aim of the work is to develop the magnetic sensor calibration procedure, as well as to provide the mathematical support for individual calibrator components numerical modeling. Materials and methods. The measurement procedures are described using the mathematical apparatus of metrological analysis and synthesis. To simulate a calibration field of a measure of magnetic quantity using the finite element method, we consider a method for creating a mathematical model describing the electromagnetic properties of a coil with direct current and low-frequency alternating current. The criteria for evaluating the results of the calibration magnetic field simulation are given. Results. A method for magnetic sensors calibration based on the use of a time-harmonic electromagnetic field generated by a measure of magnetic quantity is proposed. An approach to determine the required overall dimensions of a measure of magnetic quantity based on the finite element simulation of the measure magnetic field is proposed. Conclusions. The proposed calibration method is convenient due to its focus on automation. As a result of calibration measurements, a set of values is measured for each magnetic measuring transducer in the entire transducer measuring interval. The choice of a harmonic function for the calibration magnetic field generation is also due to the convenience of the hardware implementation of the procedure for generating the input signal of a measure of magnetic quantity. The measure coil model proposed in this paper is adequate to determine the required dimensions and the desired range of the output value variation of the measure at direct current. In the case of alternating and pulsed current, the model is inadequate, since the influence of inductance and winding resistance is not taken into account. However, the low frequency of the calibration field (no more than tens to hundreds of Hz) makes it possible to neglect additional analysis of transients in the circuit.

Background. Transparent conducting oxides (TCOs) are an important class of materials widely used in modern technologies, including solar cells, displays, and touch devices. However, the traditionally used tin-doped indium oxide (ITO) faces a number of problems, such as high cost, limited indium reserves, and environmental risks of its mining. In this regard, an urgent task is to search for alternative materials with similar characteristics, but at the same time more accessible and environmentally friendly. The purpose of this study is to develop and study alternative TCOs based onabundant and affordable materials, such as zinc oxide (AZO) and tin oxide (FTO), obtained by spray pyrolysis. Materials and methods. Spray pyrolysis was used to synthesize TCOs, which allows the formation of thin films with high homogeneity and good performance characteristics. Solutions of metal salts, such as zinc, tin, and aluminum acetates and nitrates, were used as precursors. The substrate temperature was varied from 300 to 500 °C to optimize the crystalline structure of the films. Results. The obtained AZO (aluminum-doped zinc oxide) coatings showed high transparency (> 90 %) in the visible range, specific resistance of ~10⁻3 Ω cm, stability at temperatures up to 450 °C.; FTO (fluorinedoped tin dioxide) – transparency of ~80 %, specific resistance of ~10⁻3–10⁻2 Ω cm, high thermal stability (up to 600 °C). Alternative materials demonstrated comparable optical properties with ITO (indium oxide doped with tin), while AZO showed lower cost and environmental safety, and FTO – better thermal stability. Conclusion. The study confirmed the possibility of using AZO and FTO as alternative TPOs with acceptable electrical and optical characteristics. AZO has demonstrated high transparency and low resistivity, making it a promising material for flexible electronics. FTO has demonstrated high thermal stability, making it a preferred choice for solar cells and other energy-efficient technologies. The use of these materials will reduce dependence on indium, reduce environmental impact, and ensure sustainable development of technologies.

Background. Currently, there is a constantly growing need for advanced measuring and control tools, including displacement sensors with high accuracy and speed, the ability to operate in difficult environmental conditions (large temperature differences, aggressive environments, mechanical loads, high humidity, high pressures, etc.). The aim of the study is to develop a contactless vibration displacement measurement system based on an eddy current sensor. Materials and methods. In solving the tasks, full-scale testing methods were used. Results. The operability of the developed system was tested and calibration characteristics were taken at high and low supply voltages, with different anchor materials. The operability of the system under conditions of exposure to high and low ambient temperatures was also confirmed.

Background. Transparent conducting oxides, such as indium tin oxide (ITO) and aluminum-doped zinc oxide (AZO), are essential materials for various electronic applications, including solar cells, displays, and sensors. Accurate measurement of their surface resistance is critical for evaluating the quality and performance of such materials. However, existing measurement methods have limitations in terms of accuracy and versatility. The four-probe method, knownfor its high precision, is an effective approach for these measurements. The objectives of this study are to develop and investigate a device for measuring the surface resistance of TCOs using the four-probe method. The device must provide high measurement accuracy, flexibility in probe configuration adjustments, and integration with a PC to automate the measurement process and data collection. Materials and Methods. The device was developed using platinum probes, adjustable micro-drives for probe positioning, a stabilized DC power source, and high-sensitivity amplifiers. The probe configuration uses a triangular arrangement, which can be adapted for various types of samples. Calibration was performed using reference samples, and measurement accuracy was verified on real materials. The software includes an STM32 microcontroller and a PC interface implemented in Python. Results. The device demonstrated high measurement accuracy (±1 %) within the range of 10 Ω/ to 10 kΩ/ and was successfully tested on ITO and AZO samples. The triangular probe configuration enabled precise resistance measurements on non-uniform materials. The software provides a userfriendly interface for data visualization and analysis. Conclusions. The developed device meets the stated requirements and can be used for quality control of TCOs in various applications requiring precise surface resistance measurements. The software component facilitates seamless integration into workflows, automating data collection and processing. Future improvements may include enhancing user convenience and expanding device functionality.

Background. Due to the large territorial extent of our country, the task of compression and transmission of medical information of various natures occupies one of the key places in providing the population with high-quality medical care. It should be noted that lossless data compression algorithms should be executed not only on common desktop computer architectures, but also on various specialized platforms used, for example, in portable medical biopotential recorders. Therefore, the task of developing and researching methods for undistorted compression of medical data is an urgent scientific and applied task, due to the development and improvement of computing technology. The aim of this work is to evaluate the methods of compression of transmitted data in biotelemetric systems using the example of compression of an electrocardiogram. To achieve this goal, it is necessary to solve the following tasks: analysis of existing methods of compression of transmitted data in biotelemetric systems using the example of compression of an electrocardiogram; selection of a method of compression of transmitted data in biotelemetric systems using the exampleof compression of an electrocardiogram. For a biotelemetric system as a radio engineering and information-measuring system, the main indicators are measurement error and reliability of data transmission. Materials and methods. The article presents a structural diagram of a biotelemetric system, based on the structure of the developed distributed cardiodiagnostic system and its communication channel, and discusses data compression methods based on redundancy reduction and wavelet transformation. Results. The analysis of the possibilities of compression methods and the calculation of the compression ratio were carried out. Conclusions. As a result of the conducted study, it was established that the wavelet transform of data is more preferable compared to the SCP-ECG standard for transmitting electrocardiographic examination data in biotelemetric systems.

Background. The paper aims at improving the autonomous power supply system for medical Internet of Things devices by introducing betavoltaic power sources. Materials and methods. The research method is based on the implementation of an experimental sample of a betavoltaic complex and testing its characteristics on a test bench. Results. The results of the work consist in the implementation of hardware and software components of the test bench (which is a debug board) designed to select the operating mode of betavoltaic assemblies included in the betavoltaic complex, testing it and formulating proposals for further use of the proposed approach for designing and hardware implementation of betavoltaic complexes as end devices providing pulse power supply for Internet of Medical Things devices. Conclusions. The conclusions are to substantiate the advantages of implementing the proposed approach, namely, using a betavoltaic complex as a power supply system for the Internet of Medical Things and further application of the obtained results in the healthcare system and medical engineering education.