Sinusoidal Signal Research Articles

Iontolysis using an electrically excited solid source of aqueous copper ions compatible with bacterial gene quantification

Iontolysis was demonstrated as a feasible low-voltage and low-frequency technique for bacterial DNA extraction. This was achieved through mild electrical excitation (3 Vpp with a 0.5 VDC offset at 5 Hz sinusoidal signal) of submerged copper thin films serving as a solid source for releasing aqueous copper ions into the bacterial sample upon electrical stimulation. The technique achieved approximately 40 % of the lysing efficiency of bead beating after 5 min. The electrical power consumption per Escherichia coli K12 bacterial sample was approximately 25 mW, making it suitable for use with existing portable analyzers. Its compatibility with the existing intercalating fluorescent dye gene quantification technique was demonstrated with high linearity (R2 = 0.97). Notably, it suggested the minimal presence of interfering species that may have been generated from the iontolysis byproducts. This compatibility is essential for existing bacterial gene quantification techniques to leverage the low electrical power consumption, simplicity of design and manufacturing, and ease of storage and shipping of the proposed iontolysis.

Control of Vibratory Feeder Device Mechanical Frequency Using the Modification of the Sinusoidal Supply Voltage Signal

In the industrial and sales processes, dosing systems of various constructions, whose operation is based on mechanical vibrations (vibratory feeders), are very often used. These systems face many problems, such as resonant frequency, flow instability of dosed product, instability of mechanical vibration amplitude, etc., because most of them are based on controlling the frequency of the electrical signal of the supply voltage. All these factors negatively affect the durability and reliability of the vibratory feeder systems. During this research, an automatic control system for vibratory feeder was created, whose control process is based on the modification of the sinusoidal signal (partially changing the signal area). In addition, such a way of controlling the vibratory feeder is not discussed in the literature. As the research conducted in this paper has shown, while using sinusoidal signal modification it was possible to achieve a stable flow rate of bulk production (the flow rate varied from 0 to 100 g/s when the frequency of mechanical vibrations changed from 1 to 50 Hz) and a stable amplitude of mechanical oscillations was achieved and equal to 1.5 mm. The control system is based on the microcontroller PIC24FV32KA302 for which the special software was developed. The thyristor BTA16 used for voltage modification of the sinusoidal signal made it possible to ensure the reliable control of the sinusoidal voltage modification process.

CMOS Design of Chaotic Systems Using Biquadratic OTA-C Filters

CMOS Design of Chaotic Systems Using Biquadratic OTA-C Filters

Increasing the accuracy of signal formation by changing the sampling rate

The problem of changes in the audio signal when changing the sampling frequency arose a long time ago, but interest in it has recently become more acute with an increase in the quality of signal formation and transmission. To some extent, this was also determined by the methods of assessing the quality of changes in the harmonic signal without taking into account changes in the actual broadcast signal. Algorithms for the formation of a new digital sequence after changing the sampling rate provided perfect quality in the conversion of the sinusoidal signal and large errors in the conversion of the real signal. Algorithms for changing the sampling rate Fd have been improved. The aim of this work is to study the features of changes in the sampling frequency in the paths of the broadcast channel and to develop algorithms for converting the sampling frequency in the frequency domain with an increase in conversion accuracy. It is shown that the algorithms for converting the sampling rate in the time domain have reached perfection and cannot be improved, so the transition to processing in the frequency domain is important. An algorithm for converting the sampling frequency in the frequency domain has been developed. The spectrum of the error signal for various types of converters is determined and the need for its compensation is determined. A method for introducing predistortions for converters with known and unknown sequence of sample rates used has been developed. The use of the results of this work makes it possible to improve the quality of broadcasting signals and information programs.

Integration of Skyhook Control in a Quarter Car with Magnetorheological (MR) Damper

Semi-active suspension (SAS) systems attenuate vibrations with minimal power Consumption and is usually paired with magnetorheological (MR) dampers which are a type of variable damper that produces high damping forces with no mechanical movement. This paper presents the analysis of a Skyhook controller in a quarter car test rig equipped with MR damper to reduce vibration peaks when excited by a sinusoidal signal which simulates the unevenness of road surfaces. The viability of Skyhook control in mitigating vibration was examined from the experiments. The study discovered that there was an improvement of 12.72% by Skyhook control when compared to passive damping based on the sprung mass acceleration of both damping modes. The Skyhook controller surpassed passive damping and was deemed a success in vibration control.

Demonstration of nonlinear tuning curve vibration response using a homemade analog sweep spectrum analyzer

A super-heterodyne sweep spectrum analyzer has been designed (using analog circuitry), built and tested to cover the 5 to 1000 Hz range. The analyzer employs a linear ramp voltage versus time, driving a voltage-controlled oscillator VCO that generates a sweep from 32.768 kHz to 33.768 kHz in 70 s. An analog AD734 multiplies the VCO signal by a sinusoidal signal (generated by a watch crystal 32.768 kHz oscillator). The “mixer” signal is low-pass filtered and amplified to generate a 5-1000 Hz swept tone using a 2-in. speaker. The accelerometer (mounted on a thin circular clamped acrylic plate) vibration response involves multiplying this signal by the VCO, then filtering this “mixer” signal using a 4-stage watch crystal ladder filter with a 1 Hz bandwidth. This signal is squared and low-pass filtered to generate the time (converted to frequency) vs. mean-squared voltage response on an oscilloscope. In the demonstration, 300 g of 6 mm diameter glass beads are supported by the 11.4 cm diam, 3.2 mm thick plate and upper rigid cylindrical wall column. The nonlinear tuning curve vibration response is recorded for various incremental drive amplitudes to demonstrate that the tuning curve resonant frequency significantly decreases with increasing drive amplitude.

Leak detection in an operational underground water distribution network using active acoustics

Leaks present in the water distribution networks (WDNs) lead to an enormous loss of a valuable resource, not only affecting the economic efficiency of water utilities but also posing significant potential safety hazards, and an increased burden on infrastructure maintenance. In the past, several studies have focused on passive acoustic-based leak detection by primarily sensing and analyzing the acoustic signals emitted from the leak source. In this study, we installed a low-frequency transducer in the water column of an operational WDN near Los Angeles, California, and excited the system using steady-state sinusoidal and sine burst signals. The acoustic pressure signals inside the pipe network were measured at multiple locations using state-of-the-art hydrophone-enabled devices retrofitted to fire hydrants. The experiments were conducted in the presence of a simulated leak in the network. The leak acts as an impedance discontinuity for the acoustic wave propagation, and therefore, the excited signals undergo partial reflection at the leak location. Based on signal processing techniques, we attempt to detect and localize the leaks in the WDN. The goal of using the active acoustics is to detect small leaks and increase the range of sensing.

Dielectrophoretic force characteristics toward Lactobacillus casei on an oblique-patterned electrode

Dielectrophoresis-based biochips with various microelectrode configurations have been extensively studied within the last five deca des. However, wide-field application is still challenging. This study aims to fabricate an oblique-configuration microelectrode and then utilizes it to determine the dielectrophoretic (DEP) characteristics of Lactobacillus casei based on the generated non-uniform electric field. The electric field distribution on microelectrodes was simulated with Quickfield 6.6 student version. The microelectrodes were fabricated using a copper film on a glass substrate. The DEP characteristic of Lactobacillus casei was investigated by applying a sinusoidal AC signal to microelectrodes in medium solution with an electrical conductivity of 0.05 S/m. The electric-field simulations show that the strongest electric-field was generated on the tip of electrodes spacing, and the weakest electric-field was generated on the inner of electrodes spacing. The negative-DEP force on Lactobacillus casei was observed at the frequency of 60–130 kHz, while the positive-DEP force was observed at the frequency of 380–700 kHz, both at voltage of 2–6 Vpp. The nDEP force led Lactobacillus casei to be pushed toward the weak electric field on the inner of electrodes spacing, and the pDEP force induced Lactobacillus casei to be attracted toward the strong electric-field on the tip of electrodes spacing. This study implies that the proposed oblique-microelectrode platform has promising application for bioparticles separation.

Improved Sensorless Control Strategy for IPMSM Using an ePLL Approach With High-Frequency Injection

This paper proposes an improved sensorless control strategy for interior permanent magnet synchronous motor (IPMSM) using high-frequency (HF) rotating signal injection method in the stationary reference frame. Conventional HF rotating signal injection methods face the problems of long convergence time and poor stability, due to the filters used in signal demodulation process. Therefore, an improved signal demodulation algorithm based on an enhanced phase-locked loop (ePLL) is proposed in this paper. This method improves the stability and dynamic response of the system by eliminating additional filters and reducing the resulting delays. This ePLL, in addition to estimating the phase angle of sinusoidal signal, which contains the rotor position inside it, estimates its amplitude. It is shown that the proposed method has a high robustness against the uncertainties of the motor inductances. The proposed sensorless control method is verified by experiments on a 1.8-kW IPMSM drive platform.

On Distribution of Rice–Middleton Model

The probability density function in Rice–Middleton model, which describes the behavior of the single sinusoidal random signal combined with Gaussian noise is expressed in three mutually independent ways: firstly, with the aid of an integral representation of the modified Bessel function of the first kind of integer order; secondly, by a hyperbolic cosine differential operator and thirdly, applying the Grünwald–Letnikov fractional derivative. The cumulative distribution functions are also described in all these cases, and also using the Nuttall Q–function. An associated, seemingly new, probability distribution is introduced which cumulative distribution function and the raw moments of general real order are obtained whilst the characteristic function’s power series form is inferred. The exposition ends with a discussion in which by–product summations are given for the considered Neumann series of the second type built by modified Bessel functions of the second kind having integer order.

Large Eddy Simulation Combined with System Identification Method to Analyze Non-Premixed Flame Transfer Function

ABSTRACT The heat release response (HRR) of the flame is a pivotal aspect of combustion instability investigation, commonly characterized by the Flame Transfer Function (FTF). This study employed a combination of large eddy simulation (LES) and system identification (SI) techniques to derive the FTF for a methane-air non-premixed swirling burner. The influence of memory time and excitation signals within the LES+SI was investigated as only a few studies have been conducted in this direction so far, and validated against experimental data. Variations in memory time led to notable shifts in frequency and amplitude for gain peaks and valleys, with modest effects on phase delay within the 20–140 Hz range. The number of corner frequencies increased with memory time, whereby smaller memory times flattened the gain curve and underestimated phase delay, and larger memory times intensified curve undulations, distorting finer details. By minimizing the Mean Relative Error (MRE) between LES+SI results and experimental data, the optimized memory time of 0.017 s was identified, which closely aligned with the convection time of 0.0167 s. Consequently, convection time could be referenced in a priori estimation approach for memory time in a non-premixed swirling burner. In comparing FTF obtained from different excitation signals, the Superimposed Sinusoidal Signal (SINE) excelled in the gain curve within the 20–100 Hz range, accurately capturing the 30 Hz gain peak and 80 Hz valley, while the Broadband White Noise (BBWN) excelled in the phase curve within the same range, both yielding a smaller mean relative error (MRE). However, the Discrete Random Binary Signal (DRBS) demonstrated the best consistency with experimental data within the 100–190 Hz range, and boasted an MRE of 38.01% and 28.55% respectively for the gain and phase curve within the entire frequency range. Consequently, we inferred that DRBS functioned as the excitation signal with the most minimal identification error.

High resolution and large measurement range voltage sensing based on an optoelectronic oscillator utilizing an unbalanced Mach-Zehnder interferometer.

A voltage sensor with high resolution and large measurement range based on an optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The key component in the cavity to select the oscillating signal is a finite impulse response (FIR)-microwave photonic filter (MPF) which consists of a sinusoidal broadband optical signal, an unbalanced Mach-Zehnder interferometer (MZI), a section of dispersion compensating fiber, and a photodetector. The center frequency of the FIR-MPF is mainly determined by the free spectral range (FSR) of the FIR-MPF. In the lower arm of the MZI, a cylindrical piezoelectric ceramic (PZT) wrapped with a section of optical fiber acts as voltage sensing head. Due to the inverse piezoelectric effect of PZT, the variation of the voltage will cause radial deformation of the cylindrical PZT and then lead to the change of the FSR of the MZI, determining the shift of center frequency of FIR-MPF as well as the frequency of the oscillating signal of the OEO. Thus, by monitoring the shift of the oscillation frequency of the OEO using an electric spectrum analyzer or a digital signal processor, a high-speed interrogation and high-resolution voltage measurement can be realized. Additionally, in the proposed scheme, an infinite impulse response (IIR)-MPF consisting of a fiber ring resonator is cascaded with the FIR-MPF to ensure the single-mode oscillation of the OEO. The experimental results show that a total range of 1700 V voltage sensing from - 200 V to 1500 V is accomplished with the voltage sensitivity of 0.25 GHz/100 V and the resolution of 0.3 V. By adjusting the proportion of the length of single mode fiber between two branches of MZI, the impact of temperature can be greatly reduced. The proposed sensor offers advantages such as a large measurement range, high resolution, high-speed interrogation, and stability to temperature disturbances, making it highly suitable for sensing applications in smart grids.

Exact Sinusoidal Signal Tracking on a Modified Topology of Boost and Buck-Boost Converters

This contribution presents new DC–DC Boost and Buck-Boost converter topologies to track sinusoidal signals in an exact form, that is, with zero error tracking. The proposed topology considers two DC–DC converters connected to the same load, which means that the converters are not in a cascade connection. To track the exact sinusoidal reference, the control algorithm is based on the indirect control algorithm and the harmonic balance method. The main contribution is to consider two control inputs that facilitate and permit canceling out the second harmonic generated by the nonlinearity of the model, and as a result there is a single frequency in the output. The result is such that the converters can track sinusoidal signals with exactly zero error. With this, there is a reduction in the potential negative effects on systems and equipment; some numerical results are presented to corroborate the proposal.

An Inductive Method for Comprehensive Estimation of Temperature-Dependent Electrical and Thermal Properties of Conductive Ferromagnetic Materials

Reliable information about the properties of the processed materials has a significant impact on the effects of their processing. In induction heating processes, this also applies to information about the influence of temperature T on these properties. These are both thermal and electro-magnetic properties. Based on previous studies, a comprehensive experimental method is presented for estimating the temperature characteristics of thermal diffusivity, volumetric heat capacity and resistivity on one measurement station, with particular attention to ferromagnetic materials. The estimation process is carried out on an induction heating stand using forcing signals from an inverter generator. In a computer-controlled cycle that changes the base temperature level, basic measurements of thermal and electrical properties are carried out on a material sample in the form of a cylindrical disk. They are the results of the analysis of the temperature and electromagnetic responses of a material sample to short- and long-term step pulses of a sinusoidal excitation signal with a frequency of approximately 40 kHz. The presented estimation method can be treated as a final method or a preliminary procedure for radically narrowing the variability in decision variables inthe optimization process of simultaneous determination of the sought material characteristics.

Development and Validation of a 3-D Analytical Fluidic Model in Cartesian Coordinates for a Magnetic Refrigeration Application

This paper focuses on the development and validation of a three-dimensional (3-D) analytical model based on the formal resolution of the incompressible Navier-Stokes equations in Cartesian coordinates. This analytical fluidic model calculates the evolution of the fluid flow velocity for various pressure gradient shapes (i.e., square, trapezoidal, ramp, triangle, sinusoidal signals, etc.), with or without mean value, using Fourier series. The model can consider square and rectangular channels of any dimensions in terms of height, width, and depth. It allows for the study of different types of fluid flow and geometries. The introduction highlights the significance of analytical modeling, particularly in the context of Magnetic Refrigeration (MR) technologies. The model assumptions and governing equations are presented. The results obtained from the analytical model are validated and show good convergence with those obtained using the COMSOL Multiphysics® software. The comparison demonstrates a high level of agreement between the two models. The analytical model performs well in terms of computation time and accuracy. It will be coupled with an analytical thermic model and used to optimize Active Magnetic Regenerative Refrigeration (AMRR) cycles. The ultimate objective is to determine an optimal pressure gradient evolution in order to maximize heat exchange in a regenerator channel.

Study of Short-Term and Long-Term Memories by Hodgkin–Huxley Memristor

Long-term memory (LTM ) and short-term memory (STM ) and their evolution from one to the other are important mechanisms to understand brain memory. We use the Hodgkin–Huxley (HH ) model, a well-tested and closest model to biological neurons and synapses, to shine some light on LTM and STM memorization mechanisms. The role of [Formula: see text] and [Formula: see text] ion channels playing in LTM and STM process is carefully examined by using three different types of input signals, namely, a step DC voltage, a positive part of sinusoidal wave and periodic square signal with read voltage. Results are analyzed based on first-order [Formula: see text] memristor and second-order [Formula: see text] memristor.

Flexi-EIT: A Flexible and Reconfigurable Active Electrode Electrical Impedance Tomography System.

Electrical Impedance Tomography (EIT) systems have shown great promise in many fields such as real-time wearable healthcare imaging, but their fixed number of electrodes and placement locations limit the system's flexibility and adaptability for further advancement. In this article, we propose a flexible and reconfigurable EIT system (Flexi-EIT) based on digital active electrode (DAE) architecture to address these limitations. By integrating a reconfigurable number of up to 32 replaceable DAEs into the flexible printed circuit (FPC) based wearable electrode belt, we can enable rapid, reliable, and easy placement while maintaining high device flexibility and reliability. We also explore hardware-software co-optimization image reconstruction solutions to balance the size and accuracy of the model, the power consumption, and the real-time latency. Each DAE is designed using commercial chips and fabricated on a printed circuit board (PCB) measuring 13.1 mm × 24.4 mm and weighing 2 grams. In current excitation mode, it can provide programmable sinusoidal current signal output with frequencies up to 100 kHz and amplitudes up to 1 mA p-p that meets IEC 60601-1 standard. In voltage acquisition mode, it can pre-amplify, filter, and digitize the external response voltage signal, improving the robustness of the system while avoiding the need for subsequent analog signal processing circuits. Measured results on a mesh phantom demonstrate that the Flexi-EIT system can be easily configured with different numbers of DAEs and scan patterns to provide EIT measurement frames at 38 fps and real-time EIT images with at least 5 fps, showing the potential to be deployed in a variety of application scenarios and providing the optimal balance of system performance and hardware resource usage solutions.

A remote self-calibration design for three-phase power monitoring terminal

In view of the situation that the existing three-phase power metering device is prone to excessive error and inaccurate measurement during long-term operation, and the device must be removed for re-calibration, a self-calibration power monitoring terminal based on NB-IOT communication is proposed. The power monitoring terminal adopts an external voltage transformer and current transformer, and the input signal is mV and mA level AC small signal. The integrated design of single-chip microcomputer and metering chip is used in the power monitoring terminal. The single-chip microcomputer reads and writes the data collected by the metering chip and displays and transmits the power data. After the remote measurement instruction is issued, the three-phase sinusoidal signal generator chip inside the system is used to simulate the voltage signal and current model, and the external voltage and current input channel are switched with the analog signal channel through the analog switch to complete the internal self-verification work of the device. This scheme can significantly reduce the workload caused by dismantling, installing and verifying the instrument, ensure the measurement accuracy of the instrument for a long time, and has great practical value.

A Method for Reducing Sub-Divisional Errors in Open-Type Optical Linear Encoders with Angle Shift Pattern Main Scale

In this research, a novel approach is presented to enhance the precision of open-type optical linear encoders, focusing on reducing subdivisional errors (SDEs). Optical linear encoders are crucial in high-precision machinery. The overall error in optical linear encoders encompasses baseline error, SDE, and position noise. This study concentrates on mitigating SDEs, which are recurrent errors within each pitch period and arise from various contributing factors. A novel method is introduced to improve the quality of sinusoidal signals in open-type optical linear encoders by incorporating specially designed angle shift patterns on the main scale. The proposed method effectively suppresses the third order harmonics, resulting in enhanced accuracy without significant increases in production costs. Experimental results indicate a substantial reduction in SDEs compared to traditional methods, emphasizing the potential for cost-effective, high-precision optical linear encoders. This paper also discusses the correlation between harmonic suppression and SDE reduction, emphasizing the significance of this method in achieving higher resolutions in optical linear encoders.

Sine Approximation-Based Comparison Method for Determining the Phase–Frequency Characteristic of Analog-to-Digital Converters

The analog-to-digital converters (ADCs) have been widely used in the applications of such as precision metrology, motion control, position and pose estimation, whose phase-frequency characteristic usually brings in an inevitable influence. In order to ensure the performance of these applications, the phase-frequency characteristic of ADCs has to be definitely determined before they are used. In this study, a new sine approximation-based comparison measurement method is presented, which accurately deter- mines this characteristic by utilizing the linear frequency modulation signal with high carrier frequency and narrow bandwidth instead of the sinusoidal signal. Experimental results demonstrate that the presented method is able to obtain the satisfactory accuracy for the phase-frequency characteristic of general ADCs and promote the improve- ment of their applications.