Oscillator Circuit Research Articles

Reduction in Optical Feedback Noise of Atomic Force Microscopy by High-Frequency Current Modulation

Introduction: With the advancement of technology, nanotechnology has emerged as a prominent research field. The Atomic Force Microscope (AFM) serves as a vital tool in nanoscience and technology, playing an indispensable role across various domains. Method: However, in the AFM photoelectric sensing system, the optical feedback noise from the beam deflection method can lead to inaccuracies in signal identification and analysis, impacting the accuracy and reliability of AFM measurements. To mitigate this interference, this study proposes a highfrequency current superposition system aimed at reducing optical feedback noise. By superimposing high-frequency currents, the semiconductor laser transitions from a single-mode to a multi-mode operational state, thereby altering its mode of operation and consequently reducing optical feedback noise during sensing. Initially, mathematical modeling and simulation analysis were conducted on the high-frequency current superposition noise reduction system to examine the impact of high-frequency current on the intensity noise of the semiconductor laser. Subsequently, the design of the high-frequency current superposition noise reduction system was outlined, encompassing the development of a constant current drive circuit, a voltage-controlled oscillator circuit, and a biasing circuit. Finally, the high-frequency current superposition noise reduction system underwent testing. Results: During the high-frequency current superposition noise reduction test, the system's Signal-to-Noise Ratio (SNR) increased from 15.57 dB to 17.81 dB, and the system's noise peak-to-peak value decreased from 8 mV to 6 mV. Analysis of the superposition frequency and noise reduction effect determined the optimal superposition frequency of the AFM photoelectric sensor system to be 400 MHz. Characterization experiments of the high-frequency superposition noise reduction system compared the clarity of Escherichia coli images before and after noise reduction. Conclusion: The aforementioned experimental results demonstrated that high-frequency current superposition is an effective noise reduction method capable of mitigating optical noise in the AFM photoelectric sensing system.

Design of novel oscillator circuit using grounded capacitors and two current mode building blocks

ABSTRACT This paper introduces a new scheme of oscillator realisation and its implementation in the form of a novel circuit, which requires two current mode building blocks and two grounded capacitors, besides two resistors. The proposed circuit generates two sinusoidal voltage outputs and operates on ±2.5 V supply voltage. The parasitic and non-ideal analysis of the proposed circuit is given. PSPICE simulation results are included in support of the proposed theory. The new proposed circuit is compatible to CMOS technology. Several possible applications are suggested as conclusive discussion to justify the new advance.

Extreme multi-stability and circuit implementation for a two-ReLU-memristor-based jerk oscillator

Memristor-based oscillation circuits are prone to produce coexisting infinite attractors depending on the initial conditions of memristors, leading to the appearance of extreme multi-stability. In this paper, we propose a novel memristive jerk oscillator by bringing two ReLU-type memristors in a simple jerk oscillator and investigate its dynamical behaviors associated with the coupling parameters using bifurcation plots and Lyapunov exponent plots. Further, we discuss the planar equilibrium state and its stability, and then numerically explore the coexisting infinite attractors driven by the initial conditions of two ReLU-type memristors. Because of the intervention of the two ReLU-type memristors, the memristive jerk oscillator has a planar equilibrium state whose stability closely relies on the initial conditions of two ReLU-type memristors, and different initial conditions cause different attractors to coexist, resulting in bidirectional extreme multi-stability. Finally, the memristive jerk oscillator is implemented by analog circuit and digital hardware platform, and the numerical results are confirmed by circuit simulations and hardware experiments.

Frequency-Controlled Fluidic Oscillators for Soft Robots.

Electronic-free controls have recently emerged as one of the main topics in soft robotics. However, electronic-free fluidic circuits still lack controllability and reconfigurability to achieve different functions. Here, reconfigurable pneumatic valves that widen the design space of fluidic circuits are presented. The significance of two parameters on the valve's operation: a pre-defined manufacturing parameter that sets the initial operational range of the valve, and a second, on-the-fly modifiable geometric parameter that shifts the behavior of the valve during operation is shown. It is demonstrated that equipping the valve with these reconfigurable features enables the tuning of fluidic oscillatory circuits as illustrated by two examples: a frequency-controlled relaxation oscillator and a reconfigurable ring oscillator. The relaxation oscillator is employed to control the actuation frequency of a soft hopper, which is able to achieve 80 to 125 hops min-1 and a hopping speed ranging from ≈1 to ≈1.185 BL s-1. Additionally, the reconfigurable ring oscillator is used to demonstrate how each output frequency can be controlled independently, via a soft robotic crawler that can navigate in three directions, and a volume-controlled fluidic pump able to achieve mixing of solutions in environments where electronic components cannotoperate.

Research on preparation and stability of high viscosity carbon nanotube-modified PAO20-based magnetic fluids

The preparation of high-performance magnetic fluids with high viscosity, high saturation magnetization and high stability, has remained a pivotal challenge limiting the advancement of associated applications. In the present study, we synthesized modified magnetic nanoparticles through an innovative approach combining in-situ carbon nanotube (CNT) generation with chemical co-precipitation. These nanoparticles were then co-coated with OA/PIBA, resulting in the preparation of advanced PAO20-based magnetic fluids. The effects of CNT modification on particle microstructure and magnetic properties were studied by transmission electron microscopy and vibrating sample magnetometer, the magnetoviscous properties of magnetic fluids were studied by a rotating rheometer equipped with a magnetic field module, and the stability of the prepared magnetic fluids under a strong magnetic field was tested by a self-made LC oscillation circuit. The results show that the saturation magnetization of the prepared magnetic fluids surpasses 32 emu/g, while their viscosity reaches a remarkable 6625 mPa·s (at 0.24 T, 100 1/s shear rate and 25 °C), which is significantly higher than that of traditional magnetic fluids (usually about 100 mPa·s). Furthermore, when exposed to a 0.6 T magnetic field, the magnetic fluids could exhibit Rosensweig instability that persists for over 468 h. The stability is at least 93 times superior to that of unmodified PAO20-based magnetic fluids. Based on these encouraging results, it can be fully predicted that the CNT-modified PAO20-based magnetic fluids developed in this study will play a pivotal role in various applications, including sealing, lubrication, and vibration reduction. Their exceptional properties will hold immense promise for numerous engineering applications.

Multistability of bursting rhythms in a half-center oscillator and the protective effects of synaptic inhibition.

For animals to meet environmental challenges, the activity patterns of specialized oscillatory neural circuits, central pattern generators (CPGs), controlling rhythmic movements like breathing and locomotion, are adjusted by neuromodulation. As a representative example, the leech heartbeat is controlled by a CPG driven by two pairs of mutually inhibitory interneurons, heart interneuron (HN) half-center oscillators (HCO). Experiments and modeling indicate that neuromodulation of HCO navigates this CPG between dysfunctional regimes by employing a co-regulating inverted relation; reducing Na+/K+ pump current and increasing hyperpolarization-activated (h-) current. Simply reducing pump activity or increasing h-current leads to either seizure-like bursting or an asymmetric bursting dysfunctional regime, respectively. Here, we demonstrate through modeling that, alongside this coregulation path, a new bursting regime emerges. Both regimes fulfill the criteria for functional bursting activity. Although the cycle periods and burst durations of these patterns are roughly the same, the new one exhibits an intra-burst spike frequency that is twice as high as the other. This finding suggests that neuromodulation could introduce additional functional regimes with higher spike frequency, and thus more effective synaptic transmission to motor neurons. We found that this new regime co-exists with the original bursting. The HCO can be switched between them by a short pulse of excitatory or inhibitory conductance. In this domain of coexisting functional patterns, an isolated cell model exhibits only one regime, a severely dysfunctional plateau-containing, seizure-like activity. This aligns with widely reported notion that deficiency of inhibition can cause seizures and other dysfunctional neural activities. We show that along the coregulation path of neuromodulation, the high excitability of the single HNs induced by myomodulin is harnessed by mutually inhibitory synaptic interactions of the HCO into the functional bursting pattern.

Информационные свойства частотных характеристик динамической системы резания при диагностике износа инструментов

Introduction. One of the directions for increasing the efficiency of cutting is related to the creation of tool wear diagnostic systems. Algorithms and devices have been developed that evaluate wear based on analysis of the vibroacoustic emission signal. These algorithms, as a rule, do not reveal the nature of its formation and the reasons for the change as wear develops. Subject. The paper is devoted to the analysis of the reasons for changes in vibration properties with the development of tool wear. The aim of the work is to study the changes in the frequency characteristics of a dynamic cutting system caused by the development of wear, and to build diagnostic information models on this basis, as well as its use in industry. Method and methodology. The results of mathematical simulation of a perturbed dynamic cutting system are presented, in which the observed vibration sequences are a consequence of disturbances transformed by a dynamic system, the parameters of which depend on wear. Two frequency ranges are considered. Results and discussions. The first range includes frequencies that lie within the bandwidth of the instrument subsystem. The second is outside of it. In the first frequency range, it has been analytically and experimentally proven that the development of wear leads to fundamental changes in the frequency properties of the cutting system as a converter of disturbances into tool vibrations. There is a shift in the natural frequencies of the oscillatory circuits formed by the cutting system, a decrease in its quality factor, and as wear develops, some identified features of the vibration spectra appear, including the ratio of the low-frequency and high-frequency parts of the spectrum, etc. In the second frequency range, a model of force emission in the form of a random pulse sequence is considered and wear is displayed in it. The results of studying the coherence function between the forces acting on the tool and vibrational displacement are presented. Information models of wear are proposed, an example of an information model of wear and the results of its use in industry are given.

From resonance to chaos by modulating spatiotemporal patterns through a synthetic optogenetic oscillator

Oscillations are a recurrent phenomenon in biological systems across scales, but deciphering their fundamental principles is very challenging. Here, we tackle this challenge by redesigning the wellcharacterised synthetic oscillator known as “repressilator” in Escherichia coli and controlling it using optogenetics, creating the “optoscillator”. Bacterial colonies manifest oscillations as spatial ring patterns. When we apply periodic light pulses, the optoscillator behaves as a forced oscillator and we systematically investigate the properties of the rings under various light conditions. Combining experiments with mathematical modeling, we demonstrate that this simple oscillatory circuit can generate complex dynamics that are transformed into distinct spatial patterns. We report the observation of synchronisation, resonance, subharmonic resonance and period doubling. Furthermore, we present evidence of a chaotic regime. This work highlights the intricate spatiotemporal patterns accessible by synthetic oscillators and underscores the potential of our approach in revealing fundamental principles of biological oscillations.

Readout circuit for a ZnO bulk-acoustic-wave X-ray dose rate detector

Bulk Acoustic Wave (BAW) resonators based on piezoelectric semiconductors are radio frequency devices that can convert X-ray dose rate into resonant frequency offset, which exhibit strong anti-interference capabilities and low power consumption and are suitable for wireless sensing systems. In this study, we designed a readout circuit for a ZnO BAW X-ray dose rate detector. (0001)-oriented ZnO single crystals were used to fabricate the high-quality BAW X-ray detector. Under dark field and X-ray irradiation conditions, the resonant frequency offset of the detector was recorded via the readout circuit. The readout circuit consists of an oscillator circuit based on a Pierce oscillator circuit structure, a frequency mixing circuit, and an STM32 microcontroller. This design offers higher frequency stability and lower phase noise. In practical applications, it can replace the expensive and bulky vector network analyzer for detecting and storing the resonant frequency of BAW resonators with the advantages of fast readout speed and portability.

High-throughput true random number generator based on a dual-input oscillation circuit

The rapid development in the fields of information encryption, key generation, and algorithm initialization requires an increasing rate of true random numbers, making it necessary to design a fast true random number generator. In this work, a dual-mode conversion high throughput true random number generator (TRNG) based on a dual input oscillating XOR circuit (DIO-XOR) is proposed, which is designed using DIO-XOR, combined with a MUX selects the feedback mode of the whole circuit: self-feedback/mutual feedback. It is verified by automatic layout and routing on Xilinx Artix-7 and Kintex-7 FPGAs with a throughput rate of 650Mbps, which is achieved with low hardware overhead, and passes the entropy estimation test suite, NIST SP800-90B, as well as TESTU01 with high entropy, the sequences generated in the temperature-voltage fluctuation test pass the NIST SP800-22 test with good robustness.

Device and circuit-level performance evaluation of DG-GNR-DMG vertical tunnel FET

This work presents the comparative study of Graphene Nanoribbon (GNR) based channel Double Gate (DG) Dual Gate Material (DMG) Vertical tunnel Field Effect Transistor (VTFET) performance with all Silicon material Tunnel Field Effect Transistor. The two-dimensional (2D) material GNR has been proposed in the channel material to enhance the device performance due to its low bandgap, high mobility, and high saturation velocity. The proposed device's DC, RF, and circuit-level performance analysis has been carried out for the first time. GNR-based channel VTFET shows a better average subthreshold swing (SSAVG) of 16 mV/decade compared to Silicon Vertical Tunnel FET (36 mV/decade) at a drain voltage VDS = 0.5 V. The study of temperature effects on the DC parameters is also included along with the analog/RF FOMs for the proposed two structures. In addition, the performances are compared with other reported works; it is observed that DG-GNR-DMG-VTFET offers better results than Silicon (Si)-based VTFET and other said TFET work. Finally, circuit-level analysis has been done by designing inverter and ring oscillator circuits for the proposed structures, and performance is compared in these two devices. The market-available Silvaco ATLAS TCAD simulator has been used for device-level simulation. Further, circuit-level analysis has been carried out in the Cadence Virtuoso tool using a look-up table-based Verilog-A model.

An extreme multistable circuit based on a new memcapacitor and a new meminductor

Expanding the definition of memristor gets memcapacitor and meminductor. Because there are very few physical memory elements, it is very meaningful to apply its equivalent model to the study of physical circuits. In this paper, based on the definition of the memory element, a new memcapacitor and a new meminductor are proposed, and a chaotic oscillator circuit is constructed based on them. Whether the two memory elements have memory characteristics is analyzed. The range of equilibrium points of the chaotic oscillator circuit is determined. The dynamical behavior of this chaotic oscillator circuit is analyzed by the Lyapunov exponent spectrum (LEs), bifurcation diagram (BD) and spectral entropy complexity (SE). Finally, Multisim software is used to verify the correctness of the simulation, and the physical realizability of the system is verified by the DSP platform. The results of the research help to better utilize this chaotic oscillator circuit in the field of communication encryption.

Interruption characteristic of 3%C5F10O/97%CO2 gas mixture in a 40.5 kV circuit breaker

The C5F10O/CO2 gas mixture is one of the most promising SF6 alternative gases at the present stage, which was initially applied in high-voltage electrical equipment. This paper mainly studies the interruption performance of 3%C5F10O/97%CO2 gas mixture (k = 3%) with a charging pressure of 0.6 MPa in high-voltage circuit breakers. First, the thermodynamic parameters, transport coefficient, and net radiation coefficient were calculated for k = 3%. On this basis, a 40.5 kV circuit breaker was used as a prototype to establish the magnetohydrody-namic model for breaking 20 kA short-circuit current, and the arc temperature and pressure distribution in the arc extinguishing chamber of the circuit breaker were calculated. The LC oscillation circuit was used to build an arc-extinguishing characteristic test platform to verify the accuracy of the numerical calculation. Finally, based on the Mayr arc model and the critical electric field strength, the post-arc thermal breakdown and electrical breakdown characteristics of SF6, CO2, and k = 3% were quantitatively analyzed. The results show that under 0.6 MPa, the thermal breakdown performance of k = 3% is about 89.7% of SF6, which is nearly twice higher than that of CO2 and has better thermal breaking ability. The electrical breakdown performance of k = 3% is about 20.4% of SF6, and the probability of electrical breakdown in the front end of the fixed contact is high. This problem should be paid attention to in the design of high-voltage circuit breakers. This study can provide a reference for the development and optimization of environmentally friendly high-voltage circuit breakers.

Series Oscillatory Circuit with Eddy Losses

Series Oscillatory Circuit with Eddy Losses

Studies of the influence of the degradation of the capacitances of an inductively coupled oscillator circuit on the characteristics of the wireless power supply module of an implantable spinal cord stimulator

Studies of the influence of the degradation of the capacitances of an inductively coupled oscillator circuit on the characteristics of the wireless power supply module of an implantable spinal cord stimulator

A Development of a Coarse Particle Concentration Measurement System Using a Crystal-Based Sensor and a Dust Sensor for Air Quality Measurement

QCM or quartz crystal microbalance is a non static crystal that can be used as a mass sensor. As a piezoelectric crystal, a QCM generates an electrical signal with a specific frequency. The frequency change can be utilized as a frequency counter in a mass measurement system. This study aims to develop a coarse particle sensor system using a QCM and an oscillator circuit. In line with this, this study uses an oscillator circuit and a QCM for a sensor development. Thus, the frequency measurement of the QCM contains an oscillator and a signal conditioner connected to a microcontroller. For this purpose, an Arduino Nano was used as the signal processing, while a QCM was used as a coarse particle sensor and compared to a digital dust sensor (Winsen ZH03). The sensor system was evaluated using a fixed-type crystal connected to an oscillator: 2.5 MHz - 7.2 MHz. Arduino Nano processed the frequency signal generated by the developed oscillator. The results show that the sensor system has a stable output signal compared to the comparator. There is a linear correlation between the frequency measured by the system and the oscilloscope (99.73%). It can be concluded that the sensor system can measure coarse particle concentrations from 32-620 ug/cm3 (frequencies from 2 MHz to 7.2 MHz) with a response time of 1 second. The system has an accuracy of 99% and a resolution of 1 Hz.

Development of stability charts for double salience reluctance machine modeled using hill’s equation

The paper presents a novel algorithm for the development of stability charts. The second-order differential homogeneous equation describing a double salient reluctance machine with a capacitance connected to its stator winding is transformed into hill’s equation. The circuit components are the stator coil time-varying inductance of a double salient reluctance machine, capacitance and resistance. All these are modeled by hill’s equation. The double salient reluctance machine acts as an energy conversion system. The maximum and minimum inductance of the energy conversion system is measured in laboratory by inductance, capacitance, and resistance (LCR) meter. These values help to determine the inductance modulation index. The inductance modulation indetx, the characteristic constant and the characteristic parameter obtained from modeling equations are used in the MATLAB/Simulink model. The MATLAB/Simulink simulations generate stable and unstable oscillations to form stability charts. The proposed stability charts are in good agreement with the Ince-Stritt stability chart, which is widely applied in physics, mechanics and in electrical engineering, especially where the state of stability of a system or an electric oscillatory circuit is to be determined.

Design of a Crossroad Traffic Light System

Nowadays, the situation of traffic jams is gradually increasing, and the demand for intelligent traffic lights is increasing as well. This paper designs a crossroad traffic light based on sequential logic using NI Multisim 14.0 virtual simulation software. The design includes: using 555 timer to build a second pulse oscillator circuit which outputs clock signal. Using 74LS169 counting chip to build timing circuit. Set up state control with 74LS74D trigger. Using nixie tubes and 74LS47 decoder chips to build the timing display circuit. Finally, logic gate and LED lights are used to build the display circuit of traffic lights. Next, how to design intelligent traffic lights is discussed based on this design combined with image monitoring technology. The feedback bit of image processing technology is added to the designed circuit, so that the circuit can change the green light duration with the traffic flow, and the designed circuits are also becoming smarter.

About Cosmic Microwave Background Radiation (CMBR)

Because the CMBR follows the PLANCK's radiation law more or less exactly, it should, because of the indistinguishability of individual photons, apply to a whatever black emitter. Therefrom arises the guess, that the existence of an upper cut- off frequency of the vacuum could be the cause for the decrease in the upper frequency range. Since the lower-frequent share of the curve correlates with the frequency response of an oscillating circuit with the Qfactor ½, it is examined, whether it succeeds to approximate the Planck curve by multi-plication of the initial curve with the dynamic, time- dependent frequency response of the above-mentioned model. Reason of the time-dependence is the expansion of the universe. This work is based on a model published in [1]. It is shown, that the PLANCK graph can be approximated by application of the cumulative frequency response given by the model, upon the spectrum of an oscillatory circuit with the Q-factor ½. Furthermore, the progression of frequency, energy and entropy is analysed. The results point out, that origin and progression of the CMBR have elapsed in a totally different manner than generally assumed. Because photons behaved like neutrinos immediately after BB they did not interact with other matter then. Thus, we can exactly calculate back to 8.08·10–106s instead of 379,000 years after BB. Section 6 has been reworked.

Preparation and characterization of high stability silicone-based colloidal magnetic fluids

The Fe3O4 magnetic nanoparticles were prepared using a chemical co-precipitation and were coated with surface-active agents including silane coupling agents KH550 and KH792, carboxyl-functionalized silicone oil, and amine-functionalized silicone oil. In this study, the four types of magnetic nanoparticles coated with different surface-active agents were characterized using XRD, FTIR, TEM, VSM, etc. to determine the effects of different surface-active agents on the magnetic nanoparticles. Furthermore, four different types of silicone oil-based colloidal magnetic fluids were prepared, and their stability was analyzed using an LC oscillation circuit. The results show that the magnetic nanoparticles coated with carboxyl-functionalized silicone oil have an average particle size of about 12.4 nm and a saturation magnetization of 65.2 emu/g. They exhibit the strongest dispersion stability in the base fluid, and the prepared silicone oil-based colloidal magnetic fluids can remain stable under a magnetic field for up to 2 months without sedimentation. Moreover, they exhibit excellent viscosity-temperature performance, which enhances the practical application value of silicone oil-based colloidal magnetic fluids.