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One of the major study areas in VLSI system design is the creation of an area-efficient, high-speed adder. So this paper focused on an effective adder design as an Area Effective Novel Sum Generator (AENSG) to make it suitable for real-time applications. The major operations involved in this adder are Brent Kung addition, group kill and generate (KG) signal generation, Kill Generate Propagate (KGP) signal generation, and various sum generation categories. In the sum-generating block, AENSG is utilized to minimize the space by a reduction in the number of logic gates. Xilinx ISE 13.1 is used to synthesize and validate the suggested adder design. The 64-bit AENSG adder has 37.98%, 9.09% lesser number of logic gates and 34.81%, 28.40% lesser delay when compared with PPF/CSSA_4 and hybrid adder respectively. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new resistance to frequency converter. The design is based on a shadow signal generator that produces square and triangular waveforms. The oscillator frequency can be changed using an external circuit (shadow oscillator). This method will make the conversion speed better than the conventional oscillators, and the frequency varies linearly with the resistance variation. The circuit is built using widely available commercial integrated circuits, and powered from a ±5‐V DC supply. The recommended setup is suitable for instrumentation where the oscillation frequency is directly proportional to the variation in the resistance of the sensor. The functionality of the proposed design was confirmed by experimentation and simulation. The oscillation's frequency can be changed to be nearly 10 times greater than its starting value, according to the results. [ABSTRACT FROM AUTHOR]

There are few distributed finite-time optimization results of nonlinear multiagent systems in the published literatures, especially in the case that system nonlinearities are unknown. In this paper, distributed finite-time optimization problem is investigated for higher-order multiagent systems with uncertain nonlinearities. The agent dynamics are permitted to be heterogeneous with different nonlinearities and different orders. This problem is solved by embedded control approach-based distributed finite-time optimization algorithms, which consist of two parts. In the first part, a first-order finite-time optimal signal generator is designed, of which outputs reach the minimizer of the global cost function in finite time. In the second part, embedding the generator into the feedback loop and taking the outputs of the generator as the reference outputs of the agents, and combining finite-time control and feedback domination technique together, tracking controllers are designed for the higher-order nonlinear multiagent systems to track their local optimal reference outputs in finite time. It is rigorously proven that under the proposed distributed optimization algorithms, all the agent outputs reach a bounded neighbor region of the global minimizer in finite time. The effectiveness of the proposed control algorithms is illustrated by simulations. [ABSTRACT FROM AUTHOR]

In this study, the fundamentals of electroencephalography signals, their categorization into frequency sub-bands, the circuitry used for their acquisition, and the impact of noise interference on signal acquisition are examined. Additionally, design specifications for medical-grade and research-grade EEG circuits and a comprehensive analysis of various analog front-end architectures for electroencephalograph (EEG) circuit design are presented. Three distinct selected case studies are examined in terms of comparative evaluation with generic EEG circuit design templates. Moreover, a novel one-channel battery-supplied EEG analog front-end circuit designed to address the requirements of usage protocols containing strong compound muscle movements is introduced. Furthermore, a realistic input signal generator circuit is proposed that models the human body and the electromagnetic interference from its surroundings. Experimental simulations are conducted in 50 Hz and 60 Hz electrical grid environments to evaluate the performance of the novel design. The results demonstrate the efficacy of the proposed system, particularly in terms of bandwidth, portability, Common Mode Rejection Ratio, gain, suppression of muscle movement artifacts, electrostatic discharge and leakage current protection. Conclusively, the novel design is cost-effective and suitable for both commercial and research single-channel EEG applications. It can be easily incorporated in Brain–Computer Interfaces and neurofeedback training systems. [ABSTRACT FROM AUTHOR]

Summary Generating a quadrature signal in a single‐phase system using a second‐order generalized integrator (SOGI) requires accurate frequency information. The standard SOGI phase‐locked loop (PLL) includes frequency feedback to the SOGI. However, during grid abnormalities such as voltage sag/swell and phase angle jumps, the SOGI‐PLL faces frequency disturbances that propagate to the phase detector (PD) and affects the quadrature signal generator (QSG). Furthermore, the SOGI‐PLL having two loops dependent on each other creates loop coupling phenomena; either a change in phase or frequency affects each other. SOGI‐PLL is tuning sensitive, as the SOGI block has a gain that needs to be adjusted, increases the complexity, and affects the performance of the system. There is a trade‐off between SOGI gain and PLL parameters that needs to be considered for adequate parameter design to provide accurate grid synchronization while maintaining the stability of the system. To attain better performance, researchers have proposed derivative‐based PLL (DPLL). The conventional DPLL faces challenges to noise and harmonics amplification. This paper presents an improved DPLL for single‐phase grid synchronization under adverse grid conditions. The improved derivative‐based PLL (IDPLL) comprises two improved derivative‐based quadrature signal generator (IDQSG) blocks to extract the phase‐error information for accurately estimating phase and frequency. The detailed mathematical modeling and bode plot for the IDQSG and IDPLL are presented. The proposed IDQSG eliminates the requirement of gain tuning, hence reducing complexity. Moreover, there is no interdependent loop in the IDPLL, which significantly improves the dynamic performance. A hardware setup is developed to evaluate the performance of the system in real‐time. The experimental results are obtained using an field programmable gate array (FPGA)‐based controller. [ABSTRACT FROM AUTHOR]

Fundamental, applied and technological research in the field of torsion (taxion ets.) fields is at a beginning of a journey. Like any new direction in science and technology, it is vulnerable to criticism, since the number of emerging questions is much greater than the answers to them. Harmony is what keeps the world grounded. The universe was not created by the big bang, but rather by the harmonic oscillations of matter, the "original melody" that creates the universe over and over again. This idea is not only scientifically interesting, but also a social relevant. [ABSTRACT FROM AUTHOR]

Rotational speed measurement is important for many applications. Here, a noncontact rotational speed test method based on the detection of the periodically perturbed near-field microwave of an open-ended waveguide is proposed. Both simulations and experiments were conducted to verify the near-field microwave rotational speed sensor. The constructed rotation speed sensing system was composed of a standard open-ended WR-42 waveguide (in our measurements, a waveguide-to-coaxial adapter was used to represent an open-ended waveguide) working at ~18 GHz, a radio frequency (RF) circulator, a signal generator, a, RF detector and an oscilloscope. A rotating fan to be measured was placed close to the waveguide's mouth and, thus, the waveguide's reflection coefficient was periodically modulated by the rotating fan blades. Then, the RF detector converted this varying reflection coefficient into a direct current (DC) voltage, namely, a periodical waveform. Finally, the rotational speed of the fan could be extracted from this waveform. Measurements using both the proposed near-field microwave method and conventional optical transmission/reflection methods were conducted for verification. The effect of the rotating fan's location relative to the waveguide's mouth was also studied. The results show the following: 1. The proposed method works well with a rotational speed of up to ~5000 RPM (rounds per minute), and an accuracy of 1.7% can be achieved. 2. Metallic or non-metallic fan blades are all suitable for this method. Compared with the existing radar method, the proposed method may be advantageous for rotation detection in a constrained space. [ABSTRACT FROM AUTHOR]

This paper presents a flexible method for directly generating an orthogonally polarized dual-wavelength double pulse Pr: YLF visible laser. A theoretical model is established to reveal the oscillation mechanism of the orthogonally polarized dual-wavelength double pulse laser. Theoretical results demonstrate that the ratio of orthogonally polarized dual-wavelength laser intensity and master-slave pulse energy, along with the time delay between the master and slave pulses, can be controlled by the insertion angle of the acousto-optic element and the double step losses of the signal generator. These theoretical results have been verified in experiments. We obtained a maximum output power of 145 mW for the orthogonally polarized dual-wavelength double pulse laser, with π-polarization at 604 nm and σ-polarization at 607 nm. At a pulse repetition frequency (PRF) of 10 kHz, the pulse widths of the master and slave pulses are measured to be 29.6 ns and 65.4 ns, respectively. [ABSTRACT FROM AUTHOR]

Electromyographic (EMG) signals exhibit complex interference patterns that comprise several single motor unit action potentials (SMUAPs). Evidence of a model that can generate EMG signals and considers intrinsic characteristics, such as long-range dependence (LRD) or shortrange dependence (SRD), or that supports the study of pathology-related signals is lacking. Therefore, the present study aimed to develop an EMG signal generator based on SRD or LRD derived from firing patterns. We used a dynamic model to parameterize up to 15 SMUAP waveforms of real EMG signals extracted from a database. Then, we used relative appearance rates for some signals based on the number of SMUAPs to generate the latter randomly. Furthermore, we complemented our model by generating a random firing pattern. The synthetic reconstruction of the signals indicated a displacement compared with their respective firing patterns, with the highest error rate being 4.1%. The model of the EMG signal generator in its current state could be useful for a specialist who intends to study the behavior of the signals, starting with the exploration of synthetic signals and then proceeding to the real signals. [ABSTRACT FROM AUTHOR]

The object of this study is a wireless local Wi-Fi network for broadcasting biomedical signals, its structure, and principles of construction. The task of minimizing the power consumption of a Wi-Fi transmitter has been addressed, which provides the possibility of building a wireless system for long-term monitoring of biomedical signals. As a result, a functional diagram of a wireless Holter monitoring system based on an ESP32 microcontroller was constructed, which includes a subsystem for setting up and diagnosing system units using MATLAB software packages, an ECG signal generator, and a multifunctional PCIe board from National Instruments. Evaluation criteria and methods for minimizing power consumption by an autonomous Wi-Fi transmitter have been proposed. Methods for synchronizing the working cycles of the transmitter and receiver of the Holter monitoring system were determined. A procedure for determining the optimal biosignal measurement frequency is presented, at which the distortion of ECG signals would be minimal, which means that the signal could be transmitted without losses. The concept of constructing an algorithm for implementing a program for a Wi-Fi transmitter has been developed, ensuring parallel execution of ECG signal measurement operations and their transmission over a local network. The data from semi-naturalistic tests with an experimental Holter monitoring system with a pre-setup subsystem and using external measuring devices, a computer, and the MATLAB software environment are presented. A comparative analysis of the experimental data with primary ECG signals and ECG signals at the receiver output showed a fairly stable correspondence between the input and output ECG signals. The proposed algorithms make it possible to reduce the average current consumption of the ESP32 microcontroller to 50.5 mA. The results of the study demonstrate the possibility of constructing an energy-efficient wireless system for long-term monitoring of biomedical signals based on the Wi-Fi interface. [ABSTRACT FROM AUTHOR]

Chaotic or hyperchaotic systems have a significant role in engineering applications such as cryptography and secure communication, serving as primary signal generators. To ensure stronger complexity, memristors with sufficient nonlinearity are commonly incorporated into the system, suffering a limitation on the physical implementation. In this paper, we propose a new four-dimensional (4D) hyperchaotic system based on the linear memristor which is the most straightforward to implement physically. Through numerical studies, we initially demonstrate that the proposed system exhibits robust hyperchaotic behaviors under typical parameter conditions. Subsequently, we theoretically prove the existence of solid hyperchaos by combining the topological horseshoe theory with computer-assisted research. Finally, we present the realization of the proposed hyperchaotic system using an FPGA platform. This proposed system possesses two key properties. Firstly, this work suggests that the simplest memristor can also induce strong nonlinear behaviors, offering a new perspective for constructing memristive systems. Secondly, compared to existing systems, our system not only has the largest Kaplan-Yorke dimension, but also has clear advantages in areas related to engineering applications, such as the parameter range and signal bandwidth, indicating promising potential in engineering applications. [ABSTRACT FROM AUTHOR]

Generators used in multi-machine power systems are very affected by transient situations such as malfunctions and line breaks. In transient situations, the system becomes unstable, and oscillations increase. In particular, order modeling of synchronous generators effectively eliminates transient stability situations. To analyze this in the best way, a small signal stability analysis is performed. This study was carried out in the MATLAB-based Power Systems Analysis Program (PSAT), using the 2nd-order and 5th-order models of the synchronous generator for small signal stability analysis in a 3-machine 9-bus power system. While the 2nd-order model is used as the traditional model in synchronous generators, the 5th-order model has been developed as a dynamic order model. Especially in the 5th-order model, it was developed based on a subtemporal model for better damping of the system. In the comparisons made in both order models, the real and imaginary values and participation factors are shown in figures, while the eigenvalues, damping percentage, frequency, dominant values, and operating modes are presented in tables. By using both order models in the synchronous generator, the number of eigenvalues of the system was determined. The results obtained showed that the 5th-order model gave better results in small signal stability analysis. [ABSTRACT FROM AUTHOR]

This paper presents a new structure of an Orthogonal Signal Generator for a Phase Locked Loop (OSG-PLL), utilizing an Adaptive Notch Filter (ANF) in bandwidth as the foundation. The ANF employed to generate the orthogonal system within the Phase Locked Loop (PLL), is implemented from the parallel configuration of several Bandpass Filters (BPF), starting from a lattice-structured AllPass Filter (APF). This approach offers benefits such as simplicity and reduced sensitivity to coefficient rounding in fixed-point Digital Signal Processor (DSP) implementations. The bandwidth changes adaptively by adjusting and achieving the optimization of the filter coefficients. Two adaptation algorithms are proposed, studied, and analyzed, one utilizing Gradient Descent (GD) and another based on Proportional Control of Maximum Error (ME). A series of comparative simulations are conducted using MATLAB software to validate the most effective method among the two described algorithms. The simulation results from MATLAB and the experimental results from a fixedpoint digital signal processor (DSP), specifically the TMS320F812, are showcased and examined to assess the effectiveness of the algorithm of proportional control of the ME, which has been selected as the superior alternative, thereby supporting its theoretical development. [ABSTRACT FROM AUTHOR]

Accurate measurement of complicated multiphase flow is crucial to the safety and efficiency of petroleum and chemical industrial facilities. However, the existing multiphase flow detection techniques are not applicable to pipelines in remote regions including deserts or deep seas, due to the high cost of providing a stable power supply. Herein, a self‐powered multiphase flow sensor, composed of a liquid‐driven triboelectric nanogenerator (TENG) ‐based signal generator, a ring‐type transmitter, and a string‐type receiver, is proposed. Theoretical modeling of displacement current between transmitter and receiver implies that the received current signal can accurately reflect the wetting state of the receiver, validated by a combined experimental (accuracy above 97%) and simulation study. Coupling with a quantitative analysis algorithm, a multiphase flow detection system with numerous receiver measurement points is developed to precisely monitor various flow parameters, including slug frequency (one point), slug length (two points), and flow pattern (four points), which is verified by spontaneous high‐speed camera recordings of water–air flow. The present work provides a paradigm‐shift way to develop a self‐powered, inexpensive, and accurate technique to detect multiphase flow at remote industrial facilities. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the traditional analysis methods such as Zoom-FFT (ZFFT) heavily depend on the data length in the frequency separation accuracy when separating the unbalanced signals of the inner and outer rotors of the dual-rotor system with micro-speed difference, an improved method based on ZFFT + FT was proposed to refine the signal spectrum and accurately identify the unbalanced response of the inner and outer rotors. On the basis of sampling and filtering the micro-speed difference signal by ZFFT, DFT was used to refine the frequency segment, so as to extract the corresponding amplitude of the operating frequency components of the inner and outer rotors. The basic principles of Chirp-Z transform (CZT), ZFFT, and ZFFT + FT algorithms were introduced, and the corresponding programs of each algorithm were written based on LabVIEW software for simulation, then the signal generator was used to carry out the micro-speed difference signal extraction test and finally the dynamic balance test was carried out on the dual-rotor test bench. Data simulation and field test show that compared with the CZT and ZFFT methods, the method has better frequency resolution ability and can separate the micro-speed difference signal with higher accuracy, and has high feasibility and practicability in the dynamic balance of the micro-speed difference dual-rotor system. [ABSTRACT FROM AUTHOR]

Summary: In this paper, a vector‐sum phase shifter (VSPS) integrated with a wideband high‐gain low‐noise amplifier (LNA) for Ka‐band phased‐array receivers is presented. The digitally controlled VSPS based on the RF phase shifting architecture consists of a modified I/Q signal generator with additional inductor resonance and a programmable variable gain amplifier (VGA) based on Four 3 × 4 transistor arrays. Besides the reduced parasitic effect of the I/Q signal generator, an Equidistant Contraction Technology (ECT) is used in the VGA, to maintain higher phase shift accuracy of the VSPS. A multistage LNA with series inductor peaking is adopted to fulfill the flat wideband gain, where LC resonance networks are used as interstage matching to compensate for gain roll‐off at a higher frequency. Based on simulations in 65 nm CMOS technology, the presented LNA‐Phase shifter has achieved an average NF of 3.24–3.66 dB, and an average gain of 13.1–23.6 dB. Moreover, an RMS phase error of 1.1–12.6°, an RMS gain error of 4.2–5.6 dB, and an RMS magnitude error of 2.1–2.8 dB are maintained across 27–40 GHz, with a 360° phase shift coverage in steps of approximately 2.8125°. The chip consumes 16.83 mW from a 1.2 V supply voltage, and the occupied area is 0.65 mm2. [ABSTRACT FROM AUTHOR]

This article investigates distributed optimization of high‐order nonlinear multi‐agent systems (MASs) with disturbance under switching topologies. First, we propose a class of new distributed control algorithms for high‐order MASs under switching topologies, such that all agents asymptotically reach consensus at the unique minimizer of the sum of cost functions. Then, by constructing disturbance observer, the proposed algorithms are extended to address distributed optimization problems for high‐order nonlinear MASs with disturbance under switching topologies. In particular, both of new presented methods do not require optimal reference signal generator, which can save the computational resources of systems. In final, simulations are conducted to validate the theoretical results. [ABSTRACT FROM AUTHOR]

The deterioration of large steel structures, such as bridges and power generation facilities built in the 1960s, has become a problem. Such infrastructure requires regular inspections every few years, and many robots have been proposed for structural inspection. However, inspection technology for large steel structures by robots has not yet been established. The establishment of inspection technology in bridges is one of the most important issues in the maintenance of social infrastructure. This paper proposes a novel vibration actuator as a new robot drive source, which combines mechanical resonance and electromagnetic force and enables reciprocating movement by orthogonally arranging multiple vibration components. By controlling the phase difference of these vibration components with only a simple signal generator and amplifier, machine tests showed that reciprocating and rotating reciprocating motions with almost the same characteristics are possible. Experimental results reveal that the vibration actuator is able to pull a load mass of 150 g. In addition, motion analysis is conducted by applying the energy method and considering the effects of phase control on the linear and rotational motions of the vibration actuator. The results obtained in the machine test and the analysis results are mostly in agreement. This confirms that even if the parameters for the vibration actuator are varied, the linear and rotational characteristics of the actuator can be predicted by theoretical calculations. A new drive source for robots and the operation of electromagnetic motors capable of linear and rotational motion are established in this paper. For this reason, the possibility of realizing social infrastructure improvement for large steel structures such as bridges is demonstrated. [ABSTRACT FROM AUTHOR]

In recent years, advances in materials engineering based on adaptive electronics have found a new paradigm to optimize drawbacks in signal processing. A two-layer MnO/ZnO:Zn heterostructure envisioned for frequency adaptive electronic signal processing is synthesized by sputtering, where the use of internal states allows reconfigurability to obtain new operating modes at different frequency input signals. X-ray diffraction (XRD) analysis is performed on each layer, revealing a cubic structure for MnO and a hexagonal structure for ZnO:Zn with preferential growth in [111] and [002] directions, respectively. Scanning electron microscope (SEM) micrographs show that the surface of both materials is homogeneous and smooth. The thickness for each layer is determined to be approximately 106.3 nm for MnO, 119.3 nm for ZnO:Zn and 224.1 nm for the MnO/ZnO:Zn structure. An electrical characterisation with an oscilloscope and signal generator was carried out to obtain the time-response signals and current-voltage (I–V) curves, where no degradation is detected when changing frequencies within the range of 100 Hz to 1 MHz. An equivalent circuit is proposed to explain the effects in the interface. Measurements of switching speeds from high resistance state (HRS) to low resistance state (LRS) at approximately 17 ns, highlight the device's rapid adaptability, and an estimated switching ratio of approximately 2 × 104 indicates its efficiency as a memristive component. Finally, the MnO/ZnO:Zn heterojunction delivers states that are stable, repeatable, and reproducible, demonstrating how the interaction of the materials can be utilised in adaptive device applications by applying frequencies and internal states to create new and innovative design schematics, thus reducing the number of components/connections in a system for future sustainable electronics. [ABSTRACT FROM AUTHOR]

Due to the development of wireless communications, there has been a growth in the use of IoT devices and sensor nodes. A potential power source for powering equipment in remote or inaccessible locations is necessary. This research investigates the feasibility of employing digital television (DTV) signals as an energy harvesting system, with a focus on RF-DC conversion using a voltage multiplier circuit. Commercial 5 and 9 element yagi-uda antennas are used as receiver for ambient DTV signal. The device's performance is initially evaluated within the laboratory setting, it has been shown that when the RF signal generator is at 660 MHz, the proposed energy harvesting device can generate a maximum DC voltage of 781.3 mV and 1056.4 mV for 5 and 9 element antenna, respectively. This is based on measurement of voltage output when using the input signal from DTV base stations in Thailand. It was found that the voltage output levels decreased gradually with increasing distance ranging from 153.4 V at 0.1 km to 4.5 mV at 10 km for 5 element yagi-uda antenna. In contrast, the 9-element yagi-uda antenna consistently exhibited higher voltage levels, ranging from 354.7 mV at 0.1 km to 12.6 mV at 10 km. [ABSTRACT FROM AUTHOR]

This article presents experimental evidence demonstrating the feasibility of implementing a quasi-dual-frequency microwave signal generator using a 1 kW commercial magnetron. The injection-pulled magnetron may generate quasi-dual-frequency output with nearly identical amplitudes by injecting signal at specific powers and frequencies out of the Adler locking band. This generator offers the advantage of developing a large-power and tunable quasi-dual-frequency signal at low cost and with simple implementation. In the present study, a tunable quasi-dual-frequency signal with a frequency interval ranging from 0.48 MHz to 13.74 MHz is generated experimentally. Furthermore, the effects of anode voltage ripples on the dual-frequency outputs are experimentally investigated. An empirical relationship between the frequency interval and injection ratio is obtained and presented. In addition, neither the output power nor the efficiency of the magnetron in the dual-frequency mode decreases. This research is promising for improving microwave heating uniformity in large-scale industrial applications. [ABSTRACT FROM AUTHOR]

In this study, a novel strategy to generate sophisticated acoustic streaming vortices, which would be available for rotational manipulation of micro-/nano-scale objects, is proposed and simulated. All structural units in the microfluidic chamber are symmetric in design, and all radiation surfaces have the same settings of input frequency, oscillation amplitude, and initial phase. Different kinds of asymmetric acoustofluidic patterns can be generated in the originally static microfluidic chamber only because of the asymmetric arrangement of multiple radiation surfaces in space. The calculation results of kaleidoscopic acoustofluidic fields together with particle movement trajectories induced by cross structures with different radiation surface distributions further demonstrate the versatile particle manipulation capabilities of these functional microfluidic devices. In comparison to the existing oscillation modulation method, which requires multiple radiation surfaces with different initial phases, acoustofluidic devices with a same initial phase of all radiation surfaces can significantly reduce the required number of auxiliary signal generators and power amplifiers. The proposed generation method of acoustofluidic patterns is promising for microfluidic mixing without rotating machinery, driving operation of microrobots, and rotational manipulation of biological samples. [ABSTRACT FROM AUTHOR]

In this article, a behavioral model for RF vector‐sum phase shifters is developed to estimate their behavioral and guide the phased‐array front‐end system design. According to their building blocks, the model consists of two typical parts, quadrature signal generator and variable gain amplifiers (VGAs). The modeling process for the quadrature signal generator is based on a complex curve fitting method. For the linear VGA, the polynomial fitting method is used to fit the gain and phase responses of the VGA, the first variable is frequency, and the second variable is the control voltage. Then the complex curve fitting method is used to achieve the final frequency response. Finally, the layout simulation results of an actual phase shifter circuit are used as input, and the two modules are modeled and compared with the measured results to verify the usability of the model. [ABSTRACT FROM AUTHOR]

Fast estimation is a critical feature of the proposed modeling approach as a "forward" fast solver that has a key role in solving the "inverse" problem involved in crack sizing, especially for real‐time applications. To this end, two different inversion methods have been proposed to estimate the crack depth. The first one uses an interpolation model of the 3D direct model simulation data. The second approach is based on artificial neural networks (ANN). In this article, the rotating uniform eddy current (RUEC) probe is used to detect the normal magnetic component Bz which is defined as the characteristic signal for reconstructing the crack length and depth concurrently. Using the first approach, The Bz characteristic 3D surface is presented, and this can be modeled by a fitted polynomial interpolation equation. Thus, the crack depth can be inverted using this equation referring to the experimental or simulated Bz signal and the crack length. The ANN is outlined to determine the crack depth based on the simulated Bz signature. The move from the first inversion method to the second was flexible and useful, in which the interpolation model is used as a defect signal generator for fast building of a large and efficient database for ANN training. Both of the proposed methods proved the objectivity and accuracy of the inversion results and offered more robust engineering support for automated NDT, reducing production time and increasing productivity. [ABSTRACT FROM AUTHOR]

The sensitivity of radio receiving devices and systems used in all areas of practical applications of electronics is determined at a certain signal-to-noise ratio value. Examples of systems for which this ratio is one of the important quality indicators are given. The objective of the research is to solve the current problem of measuring the signal-to-noise ratio in a wide frequency range, simplify the requirements for measuring instruments, and improve their technical and metrological characteristics. The new principle of measuring the signal-to-noise ratio, which consists in establishing precise connections between this ratio and the parameters of noise amplitude, phase, and frequency signal modulation, is theoretically justified. The validity of using modulation meters as signal-to-noise ratio meters without changing the operation mode has been proven. At that, the signal and noise are not separated and are not measured separately. Precise connections ensure the absence of methodological measurement errors. There are three options for implementing the developed measurement principle using one industrial device (modulation meter) and providing a direct reading of the signal-to-noise ratio. In two of these options there are no restrictions on the origin and type of noise, it may be arbitrary. Taking into account the unambiguous connection between phase and frequency modulation, all options for implementing the considered principle were experimentally tested. The discrepancies between the measurement results and the initial data of the signal and noise generator are within the error limits of the generator instruments. Mathematical simulation of the developed principle for measuring the signal-to-noise ratio in the Mathcad software package has been carried out, and recommendations for using the principle have been given. The fundamental advantages of the proposed principle are its simple implementation using a single industrial device and metrological support for measuring the signal-to-noise ratio. This mode coincides with the main modulation measurement mode. Metrological support for the signal-to-noise ratio measurement mode is carried out within the framework of existing state verification plans. The main technical and metrological characteristics of signal-to-noise ratio meters obtained by applying the considered principle are determined by the parameters of existing modulation meters, i.e. a wide (up to 26 GHz) frequency range and a low (10–20%) measurement error. [ABSTRACT FROM AUTHOR]

Ocean bottom electromagnetic receivers (OBEMs) are invaluable tools for observing seafloor electromagnetic signals, primarily used in magnetotelluric (MT) sounding and marine controlled source electromagnetics (MCSEM). However, the high operational costs of deploying OBEMs require thorough pre-deployment testing to enhance the data reliability and quality. Commercial signal generators used for MT and controlled source electromagnetic (CSEM) testing often fall short of the restricted terms of the frequency range, signal-to-noise ratio, storage depth, time synchronization, and amplitude dynamics. To address these limitations, we developed a specialized marine MT and CSEM signal simulative generator. The generator employs pseudorandom number code-based white noise to simulate MT signals and uses multi-frequency synthesis and amplitude modulation (AM) to generate CSEM signals. The system is developed using a low-power microcontroller unit and a field programmable gate array platform, integrating various circuits such as power, clock, encoding, control, data storage, chopper, and amplification circuits. The generator simultaneously outputs four-channel white noise and AM signals. The white noise feature provides a wide and adjustable frequency band and amplitude, while the AM feature provides a large dynamic amplitude range and multi-frequency synthesis at various carrier frequency points. Comprehensive testing verified the performance of the proposed simulative generator. The test results demonstrate that the MT simulated signals cover a frequency range from 1 E4s to 100 Hz, providing adjustable amplitudes between 10 μVpp and 10 mVpp. The CSEM simulated signals include standard square waves, third harmonic waves, and seventh harmonic waves, with amplitudes adjustable from 10 mVpp to 10 Vpp. The proposed simulative generator enhances the efficiency of OBEM functional testing and provides essential equipment support for maintaining the quality of marine data. [ABSTRACT FROM AUTHOR]

To generate high frequency signals for frequency modulated continuous wave (FMCW) application, components such as doubler, tripler or multiplier are usually utilized to process further signals from the low frequency voltage controlled oscillator (VCO). In this paper, a phase-locked loop (PLL) is intended to be the primary part used to generate frequency modulated continuous wave (FMCW) signals from 80 to 84.8 GHz by utilizing a fundamental frequency VCO. To divide those high frequency output signal and large output bandwidth, the auto-tracking Miller divider topology is proposed. This new topology can achieve 9 GHz locking range. In order to generate FMCW signals with a straight-line triangular chirp, the cascaded PLL is used. The integrated jitter from 1 kHz to 1 GHz is 887 fs for the cascaded PLL, while the single stage PLL used 1.264 ps. Moreover, when architecture with doubler or multiplier is used, the fundamental tone has an effect towards the next systems, while the cascaded PLL does not. It can be highlighted that this work achieves the best RMS-FMerror/BWchirp and RMS-FMerror/(BWchirp × fc × Tc) with value of 0.013% and 0.77e−12, respectively. The designed PLL for FMCW signal generator is implemented in 28 nm CMOS technology. By using a supply voltage of 1.2 V, the chip consumes power of 102 mW. Including all the chip pads, the implemented circuit occupies a silicon area of 1440 µm × 820 µm. [ABSTRACT FROM AUTHOR]

This paper investigates a real-time process generator of wideband signals, which calculates waveforms in a field-programmable gate array (FPGA) using the high-level synthesis (HLS) method. To obtain high-resolution and wide-swath images, the generator must produce multiple modes of large time-bandwidth product (TBP) linear frequency modulation (LFM) signals. However, the conventional storage method is unrealistic as it requires huge storage resources to save pre-computed waveforms. Therefore, this paper proposes a novel processing approach that calculates waveforms in real-time based simply on parameters such as the sampling frequency, bandwidth, and time width. Additionally, this paper implements predistortion through the polynomial curve to approximate phase errors of the system. The parallelizing process in the FPGA is necessary to satisfy the high-speed requirement of a digital-to-analog converter (DAC); however, repeatedly multiplexing real-time calculation consumes extensive logic and DSP resources, potentially exceeding FPGA limitations. To address this, this paper proposes a piecewise linear algorithm to conserve resources, which processes the polynomial only once, acquires the difference in two adjacent values through the register and pipeline, and then adds this increment to facilitate parallel computations. The performance of this proposed generator is validated through simulation and implemented in experiments with an X-band airborne SAR system. [ABSTRACT FROM AUTHOR]

A nitrogen-vacancy center based scanning magnetic microscope can be used to characterize magnetics at the nanoscale with high sensitivity. This paper reports a field-programmable-gate-array based hardware system that is designed to realize control and signal readout for fast scanning magnetic imaging with a nitrogen-vacancy center. A 10-channel 1 Msps @ 20 bit analog signal generator, a 12-channel 50 ps resolution pulse generator, a 300 Msps @ 16 bit lock-in amplifier with proportional integral derivative control function, and a 4-channel 200 Msps counter are integrated on the platform. A customized acceleration algorithm is realized with the re-configurable field-programmable-gate-array chip to accelerate the imaging speed of the nitrogen-vacancy system, and the experimental results prove that the imaging efficiency can be accelerated by five times compared to the system without the acceleration algorithm. The platform has considerable potential for future applications of fast scanning magnetic imaging. [ABSTRACT FROM AUTHOR]

The purpose of the article is to show the advantages of a new design of a high-voltage rectangular pulse generator. Known analogues combine modules: signal generator; high-voltage key of N identical transistors (Qk, k = 1....N) connected in series; gate driver of leading Qk; high-voltage power source, its electromotive force, emf (E), feeds all Qk and load (R) of the key. In analogs, divider resistors (rk) and snubbers balance equality of voltages Uk on all Qk. Under nonideal balance conditions E ≈ 0.7NUmax, where Umax is the maximum operating voltage of Qk. The new solution differs in that the high-voltage power source sets not one but N emf Ek (Ei/Ej = const (i, j); i ≠ j; i, j = 1, 2, ..., N) and each Ek feeds its Qk through the load Rk. Experiments and simulations have revealed advantages of the new design: (1) the simplicity of the circuit and key tuning, (2) the fast transition ON→OFF for all Qk (as Rk is small, Rk rk), (3) the high pulse repetition rate, and (4) the greatly improved balancing of Uk voltages allows the Ek emf to be set so that ΣUk ≈ ΣUk, max at Ui, max ≠ Uk, max. The generator with the key based on two different MOSFETs (IXTL2N450 and IXTT1N450HV, Umax = 4500 V) and with a source where the E2 = 2E1 were used to excite vacuum ion emission from liquid Ga-based alloys. [ABSTRACT FROM AUTHOR]

Computer programming-based numerical programs are firmly established in geotechnical engineering, with rapid growth of finite element modeling and machine learning techniques gaining much attention both in practice and academia. This study is intended to expedite the dissemination of advanced computer applications in terms of finite element simulation and machine learning models by investigating the dynamic response of geomaterials subjected to vibratory loads. Several trial models were built to perform the experimental investigations with a vibratory shaker, signal generator, several accelerometers, a data collection system, and other ancillary devices. The implicit integration techniques in commercialized software were adopted for numerical simulations. After data collection from numerical simulation, models were chosen, trained, and assessed to produce predictions that were then used in this study. Several technologies, including the ensemble boosted tree, squared exponential Gaussian Process Regression (GPR), Matern 5/2 GPR, exponential GPR, and decision tree architectures (fine and medium), were used to forecast the displacement of confined geomaterial. The displacement-depth ratio was found rising to 80% in the frequency range of 5 to 25 Hz, suggesting a considerable change in the behavior of the geomaterial. The Matern 5/2 GPR model showed better accuracy with an R2 value of 0.99, indicating an outstanding predictive ability. The Matern 5/2 GPR and boosted tree models could help better understand the links between displacement and its distribution along the direction of load application. The outcomes of this study based on computer-aided finite element programs can be effectively implemented in machine learning to develop computer programs. In conclusion, the computational machine learning models adopted in this study offer a new insight for uncovering hidden intrinsic laws and creating new knowledge for geotechnical researchers and practitioners. [ABSTRACT FROM AUTHOR]

This document is an editorial for a special issue of the journal Micromachines on recent advances in microwave components and devices. The editorial highlights the importance of microwave engineering in communication, sensing, and monitoring systems, and discusses the current and emerging advancements in the field. The articles in the special issue cover various aspects of microwave engineering, including RF front-ends, filters, phase shifters, power amplifiers, antennas, microwave sensors, and programmable metasurfaces. The editorial aims to provide readers with an overview of the state-of-the-art developments in microwave technology and inspire future research in the field. [Extracted from the article]

The rotor vibration fault identification of hydro-generator is a difficult problem in hydropower station operation and maintenance. Therefore, a fault identification method based on rotor vibration signal is proposed. Firstly, for the non-stationary and non-linear vibration signals of generator rotor, singular value decomposition (SVD) is used for denoising preprocessing combined with energy difference spectrum theory; the preprocessed data is transformed into time-frequency graph by continuous wavelet transform (CWT) and formed into image data set. Then the image data set is used as convolutional neural network (CNN) input, and distributed fault feature expression is formed by CNN multi-layer pooling and convolution. Finally hydro-generator rotor fault mode recognition and classification are realized. The experimental results show that the accuracy of this method is above 99.5%, which can effectively identify the fault types of hydro-generator rotor. [ABSTRACT FROM AUTHOR]

This work investigates the prospect of rotor broken bar defect diagnosis in squirrel cage induction generator-based wind turbine using fuzzy logic system (FLS) of the stator currents. The generator current signal is analyzed through the power spectral density (PSD) to diagnose the magnitudes and frequencies associated with various defects. These magnitudes and frequency components are used to apply the system of Fuzzy logic by simulation software. [ABSTRACT FROM AUTHOR]

Most calibration laboratories prefer the Direct Comparison Transfer Method (DCTM) for a reliable and accurate calibration of power sensors in the radio frequency (RF) scope. Most studies suggest using this calibration method, with its automatic power level control (APLC) of RF signal generators. The APLC is preferred to keep the output power level of the signal generator the same, while the power sensor is calibrated and the reference power sensor is connected to the measurement system. The known APLC mechanisms are also explained for the DCTM, and a comparison of the calibration factor values carried out with and without the automatic power level control process in the DCTM is also given in this study. RF power sensor calibrations with coaxial and waveguide connector types are examined with DCTM in this study as well. This study shows that the DCTM, unless with APLC, should be applied for the waveguide power sensor's calibration at millimeter wave frequencies. [ABSTRACT FROM AUTHOR]

Deep learning algorithms often struggle to accurately distinguish between healthy and anomalous states due to the scarcity of high-quality data in real-world applications. However, these data can be obtained through a physics-based simulation model. In this research, the model serves a dual purpose: detecting anomalies in industrial processes and replicating the machine's operational behavior with high fidelity in terms of a simulated torque signal. When anomalous behaviors are detected, their patterns are utilized to generate anomalous events, contributing to the enhancement of deep neural network model training. This research proposes a method, named Simulation-Enhanced Anomaly Diagnostics (SEAD), to detect anomalies and further create high-quality data related to the diagnosed faults in the machine's operation. The findings of this study suggest that employing a physics-based simulation model as a synthetic-anomaly signal generator can significantly improve the classification accuracy of identified anomalous states, thereby enhancing the deep learning model's ability to recognize deviating behavior at an earlier stage when more high-quality data of the identified anomaly has been available for the learning process. This research measures the classification capability of a Long Short-Term Memory (LSTM) autoencoder to classify anomalous behavior in different SEAD stages. The validated results clearly demonstrate that simulated data can contribute to the LSTM autoencoder's ability to classify anomalies in a peripheral milling machine. The SEAD method is employed to test its effectiveness in detecting and replicating a failure in the support element of the peripheral milling machine. [ABSTRACT FROM AUTHOR]

The article discusses some aspects of modeling the dynamics of high-gradient pulse processes accompanying technologies using electrical discharges in a liquid medium. Due to the presence of high pressure, these technologies are successfully used for the destruction and crushing of solid materials, the processing of mineral environments, the intensification of heat exchange processes, etc. The development of a pulse signal generator with a given frequency, taking into account the influence of environmental parameters, is an urgent technical problem. The main element of electric pulse technology is a generator for providing high discharge energy at a given frequency. A brief analysis of the block diagram of an RLC generator with pulse parameters is given. The possibility of a description of an RC generator of pulsed electric-discharge oscillations based on a system of dynamic equations is shown. Numerical solutions to the dynamic equations of the model oscillator using the MatLab package are presented, and phase portraits for various parameters are shown. The graphs of numerical calculations are in qualitative agreement with the oscillograms of pulsed current and voltage and reflect the nature of the dynamic patterns. The results obtained can be used in practice to select parameters that ensure a given operating mode of electric discharge equipment. [ABSTRACT FROM AUTHOR]

With the ever-increasing number of small satellites launched into space, on-board orbit determination is becoming more and more important. Precise satellite positions are needed for constellation maintenance, formation flying, communication optimization, collision avoidance and Earth observation. In addition, accurate time information is required for the functioning of the instruments on board. Low-cost off-the-shelf Global Navigation Satellite System (GNSS) receivers and antennas, adapted to the small size and weight of the satellite, allow precise on-board orbit determination and time synchronization for even the smallest satellites. We analysed more than one year of on-board navigation solutions (NAVSOL) from 8 Astrocast CubeSats, which are equipped with our multi-GNSS single-frequency payload. Based on the residuals from a dynamic orbit fitting, we found that the quality of the NAVSOL from the Astrocast satellites varies strongly both over time and between satellites, with an RMS ranging from a few meters to several tens of meters. In this study, we focus on three main effects that influence the quality of the NAVSOL from the Astrocast satellites: (1) The orbit-fit residuals show a positive radial offset in the range of about 6 m to 15 m, which is caused by ionospheric refraction. Our data show that GNSS signals at negative elevations are very strongly affected by the ionospheric refraction and thus account for the major part of the radial offset. (2) Discrepancies between the NAVSOL positions and velocities, and simulations with a GNSS signal generator show a once-per-revolution periodicity in the out-of-plane component, with amplitudes of 2 m and 5 cm/s in position and velocity, respectively. This effect is probably due to an inappropriate dynamic model used in the real-time navigation algorithm of the GNSS receiver. (3) Depending on the location of the GNSS antenna on board the satellite, the noise level varies by a multiple. This is assumed to be due to the antenna orientations, interference of the GNSS signals with electromagnetic waves coming from the satellite platform, signal attenuation during the transmission from the antenna to the receiver and differences in the soldering or tuning of the individual GNSS antennas. These findings help us refine hardware configurations and firmware settings in preparation for future Astrocast satellites or other nanosatellite missions. By eliminating or minimizing the mentioned effects, we expect to consistently achieve an accuracy on the level of a few meters for the real-time navigation solution of commercial off-the-shelf single-frequency GNSS receivers in space. [ABSTRACT FROM AUTHOR]

Due to long-distance propagation, the received Global Navigation Satellite System (GNSS) signal power is low, making it highly susceptible to signal interference. In safety-critical applications such as unmanned aerial vehicles (UAVs), GNSS signal interference can lead to significant position, navigation and timing (PNT) service deterioration or interruption. Therefore, this work focuses on investigating the effects of Global Positioning System (GPS) jamming on a DJI Mini 2 UAV and a Garmin GPSMAP 60CSx handheld GPS receiver based on various interference signal power levels and rotation angles. The field evaluation is conducted in an open area and GPS interference signals are generated using a signal generator. The signal is emitted to the target UAV using a directional antenna, and the effect of the signal is analysed and evaluated. Then, using the same setup, the measurement is repeated by varying the rotation angles of the UAV to 0, 45 and 90°. The findings indicate that when a jammer's signal reaches approximately -110 dBm in an outdoor setting, it significantly affects GPS accuracy. The impact of GPS jamming on rotation angles is influenced by altering the UAV's position (lateral and upright) as a result of changes in antenna orientation (facing upwards or towards the interference signal). [ABSTRACT FROM AUTHOR]

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Immotile yeast cells were transiently moved in nonuniform sinusoidal electric fields using multiple pairs of micro-parallel cylindrical electrodes equipped with a sequential signal generator (SSG) to analyze cell viability at a clinical scale for the brewery/fermentation industry. Living yeast cells of Saccharomyces cerevisiae during the exponential-stationary phase, with a cell density of 1.15 × 105 cells mL−1 were suspended in sucrose medium. The conductivity (σs) was adjusted to 0.01 S m−1 with added KCl. Cells exposed in electric field strengths ranging from 32.89 to 40.98 kV m−1, exhibited positive dielectrophoresis (pDEP) with the lower critical frequencies (LCF) at 85.72 ± 3.59 kHz. The optimized value of LCF was shifted upwards to 780.00 ± 83.67 kHz when σswas increased to 0.10 S m−1. Dielectrophoretic and LCF spectra (translational speed of cells vs. electric field frequencies) of yeast suspensions during positive dielectrophoresis were analyzed in terms of the dielectric properties of the cell membrane and cytoplasm which reflect yeast cell viability and metabolic health status. The dielectrophoretic collection yield of cells using positive dielectrophoresis was reported on the monitor of sequential signal generator software to evaluate the number of living and dead cells through a real-time image processing analyzer. The spectra of both positive dielectrophoresis of the living and dead cells had distinguishable dielectric properties. The conductivity of the yeast cytoplasm (σc) of the dead cells was significantly less (≈ ≤ 0.05 S m−1) than that of the living yeast cells which typically had a cytoplasmic conductivity of ≈ 0.2 S m−1. This difference between viable and non-viable cells is sufficient for cell separation procedures. Key points: •Dielectrophoresis can be used to separate viable and non-viable yeast cells, •Cellular dielectric properties can be derived from the analysis of their dielectric spectra, •Cytoplasmic conductivity of viable cells is ≈ 0.2 S m−1while that of non-viable cells ≈ ≤ 0.05 S m−1. [ABSTRACT FROM AUTHOR]

This paper introduces a device dedicated to acoustic excitation for modal analysis of plates. A particular setup is requested since the system should produce acoustic excitation with high power in the 10...120 Hz frequency range. The system comprises a signal generator, an amplifier powered by a car starter or a battery, and a subwoofer. This system permits setting the generated frequency around the resonance frequency with reasonable frequency and amplitude stability. We present the system's design and test its performance on a rectangular plate. In our laboratory experiments, we achieved the desired structural behavior. [ABSTRACT FROM AUTHOR]

The paper focuses on the mutual influence of moisture, salinity, and particle-size distribution on soil permittivity. The Agilent E8663B Analog Signal Generator is used for measurements in the frequency range of 8 to 18 GHz using the coaxial method. It is found that the maximum amount of bound water in soil depends on the soil type and is 15.9 and 13.7% for CuSO4 and NiSO4 35 mg/kg each, respectively. A 12% growth in the silt and clay content provides a 1.3% increase in the maximum amount of bound water in soil. [ABSTRACT FROM AUTHOR]

Photonic bound states in the continuum (BICs) are highly localized optical modes that have found important applications in lasers, sensors, modulators, and harmonic signal generators. While possessing a higher quality factor (Q) as compared to leaky photonic modes, regular BICs (e.g., either symmetry‐protected or accidental BICs) normally require large cavity sizes and are usually sensitive to the fabrication imperfections that introduce lattice disorders. Moreover, the previous demonstrations of BIC lasers are mostly based on optical pumping and operated in the visible and near‐infrared regimes. Here, an electrically pumped BIC laser is demonstrated by merging two types of BIC modes based on a quantum cascade chip in the terahertz (THz) regime, which has an ultra‐compact size (with a pump area around 4λ2). The measured side‐mode suppression ratio (SMSR) can reach up to ≈20 dB, indicating a good single‐mode performance over the entire dynamic range. In addition, the emitted beam shows a nontrivial cylindrical vector beam profile, a typical topological feature of BIC lasers. This work would pave the way for practical use of the emerging BIC concepts in pursuing ultra‐compact and high‐performance electrically driven laser sources, which are highly desired in advanced optoelectronics and integrated photonics. [ABSTRACT FROM AUTHOR]

Many modern position-based applications rely heavily on the Global Navigation Satellite System (GNSS). Most applications require precise position data obtained through sophisticated hardware with a high computational capacity in the receiver. Some cost-effective applications may not require precise position data and require less complex signal processing. The use of efficient hardware and signal processing techniques to reduce the overall cost of a GNSS receiver is an active research topic. This paper considers Global Positioning System (GPS) constellation and proposes two factors to reduce the receiver complexity: sampling frequency and the number of tracking channels. A Keysight GNSS signal generator to record GPS signals, a Software Defined Radio board and a software-based GPS receiver are used in the experimentation. The sampling frequencies are 40, 20, 10 and 5 MHz considered, and tracking channels are reduced from 12 to 6 and then 4. The increase of error in the receiver position with 6 and 4 satellites is considerably small, but the number of tracking channels and signal processing requirements are reduced considerably. The GPS signals are affected by many errors; one of the significant sources of error is multipath propagation. Three distinct GPS multipath scenarios are generated for four satellite signal combinations with the GNSS simulator for the receiver performance analysis. Three multipath mitigation techniques, namely Early Minus Late (EML), Narrow correlator (NC) and strobe correlator (SC) methods, are considered because of their simple structure and fewer signal processing requirements. The error reductions of three multipath scenarios are compared, and the SC method performs better in all three multipath scenarios. [ABSTRACT FROM AUTHOR]