Signal Transmission Channel Research Articles

Smart Transfer Planer with Multiple Antenna Arrays to Enhance Low Earth Orbit Satellite Communication Ground Links

In this study, we propose a smart transfer planer equipped with multiple antenna arrays to improve ground links for low Earth orbit (LEO) satellite communication. The STP features a symmetrical structure and is strategically placed on both ends of a window, serving both indoor and outdoor environments. Using the window glass as a medium, energy transmission occurs through a coupling mechanism between the planers. The design focuses on large array antenna design, beamforming networks, and coupler design on both sides of the glass. Beamforming networks enable the indoor and outdoor antenna arrays to switch beams in various directions, optimizing high-gain antennas with narrow beamwidths. Through electromagnetic induction and filter couplers, a robust signal transmission channel is established between indoor and outdoor environments. This setup significantly enhances communication efficiency, particularly in non-line-of-sight environments.

Method for determining phase shift using two-phase interpolation transformation

This study focuses on a method for accurately determining the phase shift between two harmonic signals. The proposed technique compares the waveform of the combined signal, which is obtained by applying a two-phase interpolation transformation, with a set of predefined reference functions. This study aims to develop a method for accurately measuring the phase shift between two harmonic signals to reduce the measurement errors caused by phase asymmetry in signal transmission channels and minimize the costs associated with parameter control. The sources of error in the proposed measurement method are identified and addressed. The task involves setting up the measurement objective to determine the phase shift between two harmonic signals. This section presents the analyses of known methods for measuring phase shifts using of analog-to-digital conversion. The next step involves selecting indicators and criteria to determine how closely the investigated signal matches the reference function. Then, we propose the synthesis of an algorithm to find the extremum of the sum of squares deviations for the set of reference functions and the investigated signal, relying on the golden ratio method. Finally, the paper will analyze possible sources of error that could affect the measurement outcome. The methods used are the following: methodology for conducting digital signal processing and measuring error estimation, numerical methods for extremum search, and methodology for single-factor experiments. The following results were obtained. A proposed compensation method for measuring phase shift is based on comparing the shape of the normalized signal, which is obtained as a result of the summation of harmonic signals after their semiperiodical transformation, with a set of normalized reference functions synthesized by computational means. A list of measurement and auxiliary operations, which should be ideally conducted to implement this measurement method, has been determined. An analysis of the components of measurement errors was conducted. Conclusions. The scientific novelty of the obtained results lies in the following: a method for measuring the phase shift of a signal has been developed, which, in our opinion, should be classified as a compensatory measurement method. This will significantly reduce the error component caused by the phase asymmetry of signal transmission channels and reduce the costs of controlling parameters (up to 10%) without decreasing the quality of control; a list of the measuring and auxiliary operations necessary for the implementation of the proposed measurement method has been identified; sources of errors have been determined.

Алгоритмы передачи информации в системах управления биологическими объектами

One of the problems of the theory of management of objects with a high degree of uncertainty of behavior is solved: the development of theoretical foundations of analysis, modeling methods and improvement of bio cybernetic systems, their algorithmic and software necessary to improve the efficiency of the management process is proposed. To solve this problem, it is proposed to use the mathematical apparatus of information theory, on the basis of which the information characteristics of the control signal transmission channel from the source to the control object through the external environment are calculated, taking into account the noise of the ecosystem of the control object. The existing systems using monomodal control signals that do not carry a semantic load are analyzed, and the disadvantages and limited possibilities of improving the control systems under consideration are described. Using the example of one of the insect behavior control systems with a trichromic view, a comparison of the results obtained using various technical means used as control signal sources was performed. For improving the efficiency of control systems, which use a multimodal control signal structure, proposed various algorithms for constructing control systems using a multimodal control signal structure are considered, namely: serial and parallel circuits, combined, combining serial and parallel algorithms for using control signal sources. As a method for further improving the efficiency of control systems for biological objects with a high degree of uncertainty, it is proposed to use biological signals containing a large semantic load for the control object, which determines its behavioral response. The directions of further research are formulated in order to maximize the amount of information transmitted to the control object.

Can green technology mergers and acquisitions enhance sustainable development? Evidence from ESG ratings

AbstractIn order to better understand the impact of green technology mergers and acquisitions (GTMA) on sustainable development, the difference‐in‐differences model is applied to investigate the direct impact and underlying mechanisms of GTMA on the environment, society, and governance (ESG) in China. Additionally, we established a two‐dimensional framework of “market versus government” to analyze the heterogeneity. The results show that: (1) GTMA is positively aligned with greater ESG performance, indicating that GTMA is an effective way to enhance sustainable development. (2) GTMA fosters ESG performance by boosting green subsidies (i.e., signal transmission channel), lowering financing costs (i.e., impression management channel), and enhancing green innovation (i.e., technology synergy channel). (3) The positive relationship is largely dependent on the collaborative supervision environment (i.e., “strong” market and “strong” government) and the appropriate policy environment (i.e., “big” market and “small” government). (4) Furthermore, GTMA carries significant spillover effects, with other enterprises in the same industry improving their ESG performance. Additionally, this paper proposes targeted directions for the government and enterprises to take advantage of GTMA dividends to realize superior ESG performance.

ADP‐based robust consensus for multi‐agent systems with unknown dynamics and random uncertain channels

AbstractThis article pursues the robust consensus for linear discrete‐time multi‐agent systems with unknown dynamics and random uncertain channels. Stochastic multiplicative uncertainties depending on relative states of agents inevitably appear in the signal transmission channels. To handle these uncertainties, the distributed robust controllers are designed. Before designing this robust controller, the optimal control problem of a single‐agent system is considered first. Based on the technology of adaptive dynamic programming, a model‐free off‐policy algorithm is proposed to solve the optimal controller for every agent with fully unknown system dynamics. According to the theory of mean square stability, it is revealed that the distributed robust controller can be obtained by using the optimal controller of the single‐agent system and other related parameters without relying on the dynamic information of the systems. Besides, the relationship between uncertainty and the robust controller is described by a sufficient condition. Finally, to demonstrate the effectiveness of the theoretical analysis, a numerical example is presented.

Slepa ekvalizacija kanala za prenos signala parcijalnih pražnjenja

In the case of partial discharge signals, obtained during "online" monitoring or "off-line" tests of the generator, there is often interference between the direct and reflected signals or disturbances during propagation through the medium, i.e. the structure that transmits the pulse of partial discharges to the measuring terminal or detector. The paper describes the application of the method of "blind equalization" of the partial discharge signal transmission channel, which was shown to be able to be used to extract the direct signal of partial discharges in case of overlap with reflected signals through decorrelation of direct and reflected signals. The term "blind equalization" reflects the ignorance of the characteristics of the channel (transmission medium) and they should be computationally "separated" from the composite signal on the detector.

Сравнительный анализ точности алгоритмов частотной синхронизации для системы спутниковой связи на основе сигнала DVB-S2

The paper investigates the schemes of frequency synchronization of signal reception of satellite communication system based on DVB-S2 standard with different combinations of coarse and fine frequency synchronization algorithms, namely, the following pairs of algorithms are considered: «Edge band» and «Delay & Multiply», «Delay & Multiply» and «L&R», «Edge band» and «L&R», where the first algorithm in each pair performs the task of coarse and the second algorithm performs the task of fine frequency synchronization. The accuracy of the investigated frequency synchronization schemes is evaluated using the Root Mean Square Error (RMSE) metric of frequency offset estimation in the channel. In addition, one of the performance metrics of the algorithm is the estimation of synchronization time. The frequency shift in the signal transmission channel is set constant and equal to 20% of the signal bandwidth. Using combinations of Non-Data-Aided (blind) algorithms for coarse frequency shift estimation and Data-Aided algorithms for fine frequency synchronization, the synchronization time can be reduced by almost a factor of 2, while maintaining high accuracy of RMS estimation.

Adaptive interval type-2 fuzzy fixed-time control for nonlinear MIMO fast-slow coupled systems with user-defined tracking performance

This paper focuses on the adaptive interval type-2 (IT2) fuzzy fixed-time self-triggered control issue for a class of multi-input and multi-output (MIMO) nonlinear fast-slow coupled systems (FSCSs) with preassigned tracking performance requirements. At first, the steady-state error and dynamic response of the investigated system are synthetically weighed by introducing an improved fixed-time prescribed performance function into coordinate transformation. Second, an IT2 fuzzy adaptive self-trigged controller is designed, where the unknown continuous functions are approximated by the interval type-2 fuzzy logic systems (IT2FLSs). In addition, the 1-bit encoding-decoding mechanism (EDM) is embedded in the signal transmission channel between the controller and the actuator, which also provides a feasible solution to further reduce network bandwidth consumption under the framework of the self-triggered protocol. Stability analysis indicates that the developed control method ensures that all states of the closed-loop system are practical fixed-time bounded, and the tracking error evolves to a pre-specified performance envelope within a predetermined time. Finally, a numerical example and an application example are provided to demonstrate the effectiveness and superiority of the proposed method.

The impact of carbon risk on the pricing efficiency of the capital market: Evidence from a natural experiment in china

This paper uses the Carbon Emissions Trading (CET) as a quasi-natural experiment to empirically test whether carbon risk affects the pricing efficiency of the capital market. Using data from A-share listed enterprises, this paper finds carbon risk increases stock price synchronicity and reduces the pricing efficiency of the capital market; Institutional investors alleviate the impact of carbon risk on stock price synchronicity by increasing the information content of stock prices; Media attention based on signal transmission channels and external supervision channels improve the pricing efficiency of carbon risk in the capital market. This research provides theoretical reference and practical suggestions for China to achieve the goal of carbon neutrality and ensure the smooth operation of the financial market.

Experimental research on muffle furnace dynamic properties

Purpose. To develop the method and software for building empirical models of muffle furnaces with two heating elements. Methodology. The method for processing experimental data according to the improved algorithm, which is based on the areas method, is used for constructing empirical models of the muffle furnace. Experimental research of the muffle furnace dynamic is conducted using the following methodology. The muffle furnace is cooled to the room temperature and then the lower heater is turned on and temperatures at the furnace output are fixed using the experimental two-channel temperature controller MIC-344. The second cycle of the experimental research began by cooling the furnace to the room temperature with turning on the upper heater. Observations based on the results of the experiment are conducted until the temperature is stabilized at the two outputs of the muffle furnace. Archiving of temperature trends is carried out using the RS485/Ethernet interface and the SmartReview software (a product of private limited company “Microl”). Findings. The developed software can be used for iteratively selection of the optimal empirical model based on the criterion of the root mean square deviation of the calculated and experimental data. The calculating method for the acceleration curve based on the transfer functions coefficients with a variable discreteness step is improved in order to compare the experimental data with the empirical modeling results. Twelve empirical models were tested for four signal transmission channels in the process of experimental research. It has been established that only four of them are stable (have left-hand roots of the characteristic equation). Among the selected sustainable models, the model with the numerator polynomial equaled to two and denominator polynomial equaled to three has been established as the best model (according to the established criterion). A structural diagram is created based on the synthesized empirical model of the muffle furnace, which includes four transfer functions and cross connections. Originality. For the first time, the empirical model of a muffle furnace with two electrical energy sources has been developed, which describes its dynamic properties as the object of automatic control with high accuracy, which enables to reveal the presence of internal cross-connections, that significantly complicate the controlling process of the object. Practical value. The created empirical models with two electric sources (tens) can be used for the synthesis of the high-precision automatic temperature control system of the muffle furnace.

The Impact of the Connection Failure of Ground Solder Balls on Digital Signal Waveform

Ball-grid array (BGA) packages are widely used in digital signal devices, whose reliability and signal integrity are critical. In this research, the impact of failed ground solder balls on digital signal waveforms was theoretically modeled and analyzed, and the results were experimentally verified. A 3-D electromagnetic field model of a digital signal transmission channel with failed ground solder balls was developed to analyze the signal transmission in the frequency domain. In addition, a time-domain waveform simulation system was developed to examine the changes in the digital signal waveforms before and after degradation. Based on the structural and signal transmission characteristics of the solder area with failed ground solder balls, an equivalent circuit model of the degraded solder area was developed, which accurately predicts the effect of the failed ground solder balls on the amplitude and rising edge of the digital signals. The results obtained from the simulation were validated using experimental tests. This study fully examines the effects of the location and number of failed ground solder ball on signal transmission in both the frequency and the time domain. It provides insight and guidance regarding the impact on signal integrity of such faults, which serves to assist in improved packaging reliability and the development of fault detection strategies for such electronic systems.

Robust yaw control of autonomous underwater vehicle based on fractional-order PID controller

Autonomous underwater vehicles (AUVs) have broad applications owing to their small size, low weight, strong ability to operate autonomously, and ability to replace humans in dangerous operations. AUV motion control systems can ensure stable operation in complex ocean environments and have attracted significant research attention in marine science and technology. The main difficulties with AUV motion control include the large uncertainties of dynamic and hydrodynamic characteristics and time delay of the signal transmission channel. In this study, we propose a robust fractional-order proportional–integral–derivative (FOPID) controller design for an AUV yaw control system. First, a three-dimensional stability region analysis method is proposed to achieve fractional orders. Unlike other stability region analysis methods, the proposed method is supported by theory instead of observation. Then, the other parameters are optimized according to the robust design specifications with respect to the parameter uncertainties. Therefore, the controlled system can tolerate different parameter uncertainties and fulfill transient performance specifications while maintaining system stability. The simulation results illustrate the superior robustness and transient performance of the proposed control algorithm.

Comparative analysis of noise immunity of the information transmission channel of secondary radar systems

This paper presents the conducted assessment of noise immunity of the request signal transmission channel and response channel for flight information of secondary radar systems as part of aircraft responders. The considered system is an open single-channel queuing system with refusing due to the action in the request channel of intentional and unintentional correlated and uncorrelated (intra-system) interference and ground-based receivers that receive, process and decode flight information in the presence of fluctuation and intra-system interference in the receiving channel. The results of assessing the noise immunity of the aircraft responder in the form of the aircraft responder’s readiness factor under the action of internal and deliberate interference are given. It is shown that the principle of constructing an aircraft responder and the principle of servicing request signals and transmitting flight information do not allow ensuring acceptable probabilities of obtaining flight data at ground control points.

Application of spectral analysis for determine the phase shift of signals with equal amplitudes using full-wave transformation when measuring the characteristics of weapons

The article defines the list of technical characteristics of armaments and military equipment (ARM), the value of which is measured using phase methods. An analysis of known methods that have found wide application in measuring technology, which is designed to determine the technical characteristics associated with the measurement of phase shift during the development, manufacture and operation of weapons. Based on this analysis, it was determined that the measuring systems are designed to determine the phase shift of two harmonic signals in their composition have two channels of information transmission. This architecture of the implementation of measuring systems leads to the fact that a significant impact on the accuracy of the proposed measurement problem, makes a component of the error due to the phase symmetry of the signal transmission channels, as well as internal and external noise. As an alternative approach to solving the measurement problem of determining the phase shift of two harmonic signals, which will significantly reduce the error component due to phase asymmetry of information transmission channels, it is proposed to use the signal obtained by summing harmonic signals after full-wave transformation followed by spectral analysis. In order to implement the above approach, a measurement problem was set to determine the phase shift of two harmonic signals, using spectral analysis of the signal obtained by summing the harmonic signals after their full-wave transformation. A list of assumptions required for the synthesis of analytical relations that establish the relationship between the spectra of phases and amplitudes (power) of the signal obtained by summing harmonic signals after their full-wave transformation and phase shift of two harmonic signals. Analytical relationships are proposed that establish the relationship between the above characteristics. It is shown that the values of the spectrum of phases and amplitudes, which are calculated using the proposed expressions, differ from the values obtained in the calculations using the Fourier series coefficients, not more than 0.1%.

A stable strain gauge measurement method for monitoring in-situ stress

In-situ stress exists in all rock mass or structures, which is reflected in the deformation and failure of various underground or ground excavation in geotechnical engineering. In-situ widely used in the engineering practice, in-situ stress monitoring plays an important role in many aspects, such as mine development, slope support, and geological disaster prevention and control, etc. Strain gauge has been used to record rock deformation using Differential strain analysis (DSA), Hollow Inclusion Technique (CSIRO Cells), and other in-situ stress measurement techniques. Limited by the volume, cost, power, and connection scheme of the measuring instruments, the test data are always influenced by various immeasurable factors, such as bend of the measuring cable and change in the ambient temperature. Majority of the gauge measurement technologies are not suitable for in-situ stress monitoring because of the stability of strain gauge measurement is poor, limits the application range of the gauge measurement. A stable strain gauge measurement method can be used for medium to high-precision in-situ stress monitoring to serve various engineering developments. We made a new measurement scheme by using high-precision constant current with independent signal transmission channels to achieve a high stability and high-resolution strain gauge measurement circuit with low power consumption and space cost. The temperature drift is as low as 0.3 με/°C in 0°C–60°C temperature range at 8000 με strain input, which can achieve the measurement effect of the traditional desktop strain gauge in about 1/10th volume and very low cost. The error caused by the change of cable resistance is reduced to 1 ppm, and the error caused by the disconnection and reconnection is less than 1 με, which avoids the failures caused by various environmental factors in the monitoring process, and the installation distance of monitoring strain gauge can reach tens of meters. This creates conducive conditions for using traditional in-situ stress measurement technology with in-situ stress monitoring and establishes an efficient and low-cost in-situ stress monitoring system.

Research on the Influence Factors of EM-MWD Signal Transmission in Drill String Based on Finite Element Method

The drill string is an important EM-MWD signal transmission channel in existing electromagnetic measurement while drilling (EM-MWD) systems. In order to deeply understand the influence factors of EM-MWD signal transmission effect in drill string, the EM-MWD signal channel is modeled based on equivalent transmission line method, and finite element calculation is carried out using ANSYS software. Energy loss of different specifications of drill string in alternating electromagnetic field and influence of casing on EM-MWD signal transmission.It is found that the energy loss of EM-MWD signals in the drill string increases with the increase of power and frequency, and the increase is more obvious when the signal frequency exceeds 100 Hz. Different drill strings have different signal transmission effects, but when the ratio of drill string wall thickness to outer diameter is 0.08 ~ 0.20, EM-MWD signal transmission effect is better. Casing on the drill string can shield em-MWD signals, but when EM-MWD signals are transmitted at frequencies below 50 Hz, casing has little impact. The research results further clarify the influence of the properties of the drill string on EM-MWD signal transmission, which can provide reference for the improvement and design of EM-MWD system.

Control of high-order nonlinear systems under error-to-actuator based event-triggered framework

This paper solves the finite-time tracking problem of a class of high-order nonlinear systems under event-triggered input. Unlike existing event-triggered frameworks based on signal transmission channels from the sensor to the controller or from the controller to the actuator, these developed trigger mechanisms only compare the difference between the signal to be transmitted and the holding signal. By introducing internal trigger conditions and external trigger conditions, a novel error-to-actuator based event-triggered framework is proposed. It further considers the response of the trigger mechanism to system control performance such that the tracking performance of the system can be guaranteed while reducing the number of signal transmissions. In addition, filter-based techniques (such as the dynamic surface control method), for the first time, are utilised to eliminate some strong constraints that exist in the literature for most high-order nonlinear systems. The effectiveness of the proposed approach is evaluated on simulation examples including comparative studies and a practical example.

Field Test of Vibration Wave Attenuation Coefficient Model in Casing Medium

The casing string is a very good down-hole signal transmission channel due to its rigidity which means it can reduce attenuation in vibration wave propagation. Based on elastic mechanics theory, we obtain the wave equations of vibration propagating in the free casing, analyze the transmitting law of the vibration wave in the well fluid-casing-cement system and found that the attenuation of the vibration wave is mainly caused by the energy absorbed including the well fluid, the casing and the cement ring. Based on the attenuation factors which affect the wave propagation, we get the vibration wave attenuation coefficient model and calculate the relative attenuation coefficients in different casing strings. By detecting and analyzing the drilling plug signal in the second spud, the field test results prove the feasibility of long-distance transmission and the low attenuation of vibration wave in the casing string, and get the attenuation coefficient of casing size 9 5/8, which is similar to the simulation result.

Model for Elimination of Mixed Noise from MRI Heart Images

A method for the preliminary processing of MRI images of the heart that allows for the elimination of fluctuation and impulse noise from useful signals is proposed. These types of noise are due to the regular geometric structure of the photoelectric elements of the MRI scanner matrix and the structure of the signal transmission channel. The aim of this work is to develop a comprehensive mathematical model for eliminating noise in the signal of an MRI scanner. In this work, mathematical models of linear and median filtering of impulse noise, fluctuation, and geometric noise are implemented. The mathematical models consist of the combined use of linear and median filters for recording MRI images of the heart. In the experiments, real MRI images of the heart from six patients with different diseases were used after noise was added to them. We were able to eliminate the impulse noise, geometric noise, and fluctuation noise in the MRI images by applying our filtering techniques. The filtering technique not only removed the noise, but also increased the contrast of the cancerous volumetric heterogeneous formations in the heart region.

УСТРАНЕНИЕ ИМПУЛЬСНЫХ ПОМЕХ И ФЛУКТУАЦИОННЫХ ШУМОВ В СИГНАЛЕ ПИРОМЕТРА НА ОСНОВЕ МЕТОДА ДВУМЕРНОГО СКАНИРОВАНИЯ

A method is proposed for preliminary processing of digital data obtained by recording the temperature of a biological object with a pyrometer, which allows to eliminate fluctuation noises and impulse noise in a useful signal due to different regular hemetry structures of photoelectronic elements of the optical matrix or the structure of a signal transmission channel.