Filter Circuit Research Articles

Inflammatory Gene Expression in Livers Undergoing Ex Situ Normothermic Perfusion Is Attenuated by Leukocyte Removal From the Perfusate.

Ex situ normothermic perfusion (ESNP) is a method to evaluate and potentially recondition organs before transplantation. However, increased expression of inflammatory molecules, including by tissue-resident immune cells, may occur during the perfusion process, potentially negating the beneficial effects of perfusion. We used RNA sequencing to assess gene expression in 31 livers undergoing ESNP, including 23 donated after circulatory death (DCD) and 8 donated after brain death. In 7 DCD livers, a leucocyte filter was added to the circuit during perfusion. Biopsies were available for transcriptomic assessment in all cases at the start of perfusion and at varying time points postperfusion. During ESNP in DCD livers, we observed an increase in proinflammatory, profibrinolytic, and prorepair pathway genes. SERPINE1, encoding plasminogen activator inhibitor-1, was among the genes most significantly upregulated during perfusion in DCD livers, potentially promoting fibrin clot persistence in vasculature. We also found increased expression of monocyte and neutrophil recruiting chemokine and proinflammatory cytokine transcripts during ESNP, but several prorepair molecules, including thymic stromal lymphopoietin, were also upregulated. In both DCD and donation after brain death livers, interferon-gamma response genes were enriched, whereas oxidative phosphorylation genes decreased in organs with high perfusate alanine transaminase, a biomarker associated with adverse clinical outcomes. The inclusion of a leukocyte filter in the perfusion circuit mitigated the induction of inflammation/immune pathway genes during perfusion and was associated with enrichment in oxidative phosphorylation genes. Leukocyte removal during ESNP abrogates transcriptional changes that are associated with unfavorable clinical outcomes, potentially benefiting human livers undergoing ESNP.

A Novel Single-Stage Boost Single-Phase Inverter and Its Composite Control Strategy to Suppress Low-Frequency Input Ripples

Low-frequency pulsating ripples exist on the input side of a single-phase inverter, which bring some adverse effects and harm to the inverter and photovoltaic power generation system. In order to suppress the low-frequency pulsating ripple and reduce the filter circuit parameters, a novel single-stage boost single-phase inverter is proposed, which can suppress low-frequency ripple. And a three-closed-loop compound control strategy that can suppress input low-frequency ripples under the limitation of an energy storage inductor current and buffer capacitor voltage is proposed. The circuit topology, control strategy, key circuit parameters design, system modeling, and simulation of the inverters are deeply analyzed and studied. Simulation and experimental results show that the inverter has a good ability to suppress input low-frequency ripples.

A tunable dual-narrowband HTS filter using coding superconducting metamaterials aided by grey wolf algorithm

Abstract The design of tunable dual-narrowband high-temperature superconducting (HTS) filter based on coding superconducting metamaterials aided by grey wolf algorithm (GWA) is proposed in this paper. By virtue of the characteristics of right/left-handed bands and scale of deep sub-wavelength, the tunable metamaterials unit loaded with varactor is designed, with coupling types of coding pairs further studied. A tunable sixth-order HTS filter circuit is then constructed, whose layout is effectively optimized by newly developed GWA method. Simulated frequency responses demonstrate that the center frequencies of dual-band respectively locate at 170.1-177.2 MHz (Band I) and 185.2-194.1 MHz (Band II), with 3-dB fractional bandwidth (FBWs) of 0.65%-0.61% and 0.62%-0.57%. The deeply miniaturized circuit size is 0.037×0.046 λ2 g, and the close-to-band rejection level reaches 80-dB. Experimental results of fabricated prototype measured at 70 K validate the feasibility of described design method for high order tunable HTS filter.

Research on key circuits of high‐precision servo channel loading card for wing fatigue testing

AbstractThe key circuits of servo channel loading card with high‐precision data acquisition and output functions for wing fatigue testing are studied and improved in this paper. To solve the problem of large offset voltage in some op‐amps, non‐inverting combined amplifier circuit (NCAC) and inverting combination amplifier circuit (ICAC) are proposed by utilizing precision op‐amps combined with wide voltage and high‐power output op‐amps. In the force signal acquisition section, a non‐inverting combined zeroing filter circuit (NCZFC) is proposed to improve the precision of signal acquisition. In the excitation source output section, a non‐inverting combined excitation output circuit (NCEOC) is proposed to improve the precision of the positive excitation output; an inverting combined excitation output circuit (ICEOC) is also proposed, which improves the precision of the negative excitation output and also realizes the inversion of the input and output signals. In the servo drive output section, a non‐inverting combined voltage and current conversion circuit is proposed to improve the precision of voltage and current outputs, which has two modes of non‐inverting combined voltage output (NCVO) and non‐inverting combined current output (NCIO) modes. Simulation experiments in Multisim and actual tests have been carried out on the above improved circuits to verify the stability and precision.

Numerical harmonic modelling of low wattage LED lamps based on parameter estimation algorithms

This paper presents a numerical harmonic modeling approach for 18 low-wattage Light-Emitting Diode (LED) lamps. The proposed methodology utilizes meta-heuristic algorithms, namely Multi-Stage Ant Colony Optimization (MSACO) and Harris Hawk Optimization (HHO), to estimate optimal parameters for the equivalent circuits. Additionally, the study examines eight different configurations of Electromagnetic Interference (EMI) Filter circuits, including their respective parameters, which function as front-end circuits for the Full Bridge Rectifier (FBR) of the LED drivers. Through extensive investigations, the primary objective is to establish generalized and accurate models for various EMI filter circuits that can be universally applied, with validation through comparison against experimental results. Under both MSACO and HHO, the lowest average total error ranges were observed in the LC-Filter and CL-Filter configurations, with errors ranging from 21.302 % and 22.769 %, respectively. On the other hand, the L-Filter and R-only configurations exhibited the highest average total error ranges, with errors of 42.376 % and 44.648 %, respectively. Notably, this paper introduces a non-intrusive, non-invasive method for estimating optimal parameters based solely on measurements obtained from the input terminals of the LED lamps.

Bandwidth enhancement of piezoelectric MEMS microspeaker via central diaphragm actuation and filter integration

Abstract This study presents the piezoelectric microspeaker design consisted of the central-diaphragm, connecting-spring, and cantilever-plate actuators to create two resonances in the desired frequency range. In addition to the cantilever-plate actuator, the electrical routing and piezoelectric film are designed to drive the central-diaphragm independently. According to the stress distributions on the microspeaker structure for both lower and higher modes, the all-pass filter circuit is designed and implemented to manage the phase of input signals to the central-diaphragm, thereby changing the motion of the proposed design. Thus, the sound pressure level (SPL) beyond 1 kHz is improved and the SPL zero at specific frequency range is avoided. As a result, the bandwidth enhancement is achieved by the proposed microspeaker. Measurements are conducted under 0.707 Vrms with 9 VDC driving voltage in standard ear simulator to evaluate the performances of the proposed design. A reference design without a piezoelectric film on the central-diaphragm is also implemented for comparison. Measurements indicate, in the low frequency range (before 4 kHz), the proposed designs have over 3 dB SPL enhancement due to the excitation of central-diaphragm. Moreover, compared to the reference design, proposed designs prevent the occurrence of an SPL zero near 10 kHz (between lower and higher modes) and achieve over 15 dB SPL enhancement. When the driving frequency exceeds the higher mode (14 kHz), the proposed design with the all-pass filter eliminates the SPL zero (at 16.8 kHz) with nearly 8 dB enhancement in the 15–18 kHz frequency range. Thus, this study demonstrates the bandwidth enhancement by the proposed microspeaker design with central-diaphragm actuation and all-pass filter integration.

Implementation of Raspberry Pi As A2dp Module On The Quality of Song Reception of Humanoid Robot

This research discusses comparing the performance of Bluetooth communication on Raspberry Pi in controlling dance humanoid robots using external modules and direct communication. This research aims to understand the difference in performance between the two methods, by analyzing data transmission speed, signal stability, and communication latency that affect the quality of robot movement. In addition, this research also aims to evaluate the effectiveness of using simple filters such as low-pass filter circuits to improve the stability of Bluetooth communication on Raspberry Pi. It is hoped that this research can lead to a better understanding of the influence of both communication methods on the quality of dance humanoid robot movements.

Filter cable design with defected conductor transmission structures

Electrical cables, as the industry’s blood vessels and nervous system, require evolving distributed filtering for complex electromagnetic environment adaptability. This article introduces a filter cable design featuring an insulated cylinder coated with a defected conductor transmission structure (DCTS). The DCTS, with a well-designed etched pattern, functions as a boundary condition for transmitting specific frequency electromagnetic waves, similar to a lumped filter circuit. To validate this method, a low-pass filter cable is proposed with six-slot-ring defected structures, utilizing polytetrafluoroethylene as the inner dielectric, encased within a flexible printed circuit board (FPCB)-manufactured DCTS. The proposed cable, with precise dimensions (2.4 mm diameter, 340 mm length), demonstrates minimal insertion loss ( < 0.38 dB below 6 GHz) in the passband and rejection exceeding 23 dB at 7.7-25 GHz in the stopband. Further enhancements achieve attenuation exceeding 50 dB in the stopband (7.1 GHz to 20 GHz). Compared to traditional cables, this filter cable addresses electromagnetic compatibility (EMC) by cutting off the interference coupling path.

Application and practice of portable bi-directional DC-AC energy storage converter based on second order generalized integrator phase-locked loop and HERIC circuit

In various industries, including the production of new energy and electric vehicles, portable bidirectional converters are crucial for enhancing power supply reliability. In recent years, these converters have become increasingly normal in daily life. Bidirectional converters have not been as popular or have not been used as much due to issues with phase tracking on grids connected to leakage current in the converter system. The essential features and principles of the portable bidirectional energy storage converter proposed in this paper, which is based on a second-order generalized integrator phase-locked loop, are theoretically investigated. Formulas are also generated using small signals to address this issue. PLECS simulation software was used for parameter design and algorithm simulation to test the effectiveness of the phase-locked loop under various operating situations. Therefore, a set of appropriate phase-locked structure models for this circuit was developed. An experimental verification platform was constructed to confirm the accuracy of the design parameters: the front stage uses the H-bridge; the backstage, which uses the front stage, adopts the H-bridge; and the rear stage adopts the topology platform of the HERIC topology + LCL filter circuit. The test data indicates that, the addition of the HERIC topology and soft switching resulted in a 94 % reduction in leakage current and a 1.6 % improvement in efficiency. Analysis and comparison results of the test data confirmed the consistency between the experimental effect and the design parameters, achieving the expected effect and proving the accuracy of the topology and mathematical model. The design methodology and design parameters of this thesis are useful and instructive for similar or related research.

Double‐order negative group delay filtering function: A brilliant capability of the bilinear double‐order transfer function

AbstractIn this work, the capability to generate the negative group delay (NGD) phenomenon at those frequencies higher than a certain value, that is, the NGD high‐pass (HP) filtering function, of the bilinear double‐order transfer function has been demonstrated. Based on the Type‐I bilinear double‐order filter circuit, our theory has been verified by strong agreements between the formulae and their proof‐of‐concept (POC) circuit‐based simulation results. Both formula‐based and POC circuit‐based simulations give the minimum group delay of −5 ms yet the cut‐off frequency of 10 and 9 rad/s, respectively. Such slight deviation is caused by the approximation error of the bilinear double‐order impedance. By employing two orders, the bilinear double‐order transfer function has been found to be the basis transfer function for the NGD filtering function with the highest degree of freedom. Based on our design equation for the NGD filtering function, it can be seen that the distances between zero and pole and the characteristic frequency of the bilinear double‐order transfer function are governed by such characteristic frequency itself, the cut‐off frequency of the NGD filtering function, and the fractional order of the Laplacian operator. In addition, the effects of the fractional order of the Laplacian operator, the fractional order of the transfer function, and the ratio of the abovementioned distances to the characteristics of the newly found double‐order NGD filtering function have been studied in detail.

A GUI-BASED DATA ACQUISITION SYSTEM FOR EIT USING TWO CURRENT INJECTION METHODS

The current injection method played an essential role in the data quality of impedance measurement using the electrical impedance tomography (EIT) technique. Previous studies have largely utilized only a single current injection method with limited interface access, which restricts the effectiveness of EIT systems. In this paper, a graphical user interface (GUI)-based data acquisition system was designed to improve user interaction and optimize the control system. The system was equipped with multiple current injection methods, allowing researchers to choose which method to use in the measurement process. The designed hardware comprises a V-to-I converter circuit, multiplexer, electrodes, peak detector, and filter circuit. Testing results indicate that the V to I converter circuit has an average peak difference between voltage and current of 4.86% and an average error of 0.69% in the peak detector circuit. The multiplexer circuit switches quickly and consistently, while the filter circuit remains stable at the 50 kHz frequency used in this study. These results demonstrate that the designed circuits perform adequately and effectively, ensuring reliable and accurate measurements. Additionally, the data acquisition software, presented as a GUI, effectively facilitates the selection of current injection methods and the display of boundary data simulation (BDS) on the object. This is demonstrated by the spatial inhomogeneity patterns visible through BDS in both the adjacent and opposite methods

Automated design and optimization of distributed filter circuits using reinforcement learning

Abstract Designing distributed filter circuits (DFCs) is complex and time-consuming, involving setting and optimizing multiple hyperparameters. Traditional optimization methods, such as using the commercial finite element solver HFSS (High-Frequency Structure Simulator) to enumerate all parameter combinations with fixed steps and then simulate each combination, are not only time-consuming and labor-intensive but also rely heavily on the expertise and experience of electronics engineers, making it difficult to adapt to rapidly changing design requirements. Additionally, these commercial tools struggle with precise adjustments when parameters are sensitive to numerical changes, resulting in limited optimization effectiveness. This study proposes a novel end-to-end automated method for DFC design. The proposed method harnesses reinforcement learning (RL) algorithms, eliminating the dependence on the design experience of engineers. Thus, it significantly reduces the subjectivity and constraints associated with circuit design. The experimental findings demonstrate clear improvements in design efficiency and quality when comparing the proposed method with traditional engineer-driven methods. Furthermore, the proposed method achieves superior performance when designing complex or rapidly evolving DFCs, highlighting the substantial potential of RL in circuit design automation. In particular, compared to the existing DFC automation design method CircuitGNN, our method achieves an average performance improvement of 8.72%. Additionally, the execution efficiency of our method is 2000 times higher than CircuitGNN on the CPU and 241 times higher on the GPU.

Monolithic integrated circuit LNA 5–10 GHz

One of the features of the current stage of development of microwave electronics is the widespread use of monolithic integrated circuits. The interest of radio-electronic equipment developers in MIS is caused not only by better microwave characteristics compared to modules made using hybrid technology, but also by economic feasibility, ease of setup and reproducibility of parameters of finished products. An integral part of the transmitting and receiving paths of such systems are MMICs of low noise amplifiers. The goal of the work is to implement a matched MIC microwave low-noise amplifier with operating frequencies from 5 to 10 GHz with a noise figure of at least 1.2 dB and a gain of at least 20 dB. To develop an amplifier with operating frequencies up to 10 GHz, technology with a design standard of 0.25 microns was chosen. To meet the requirements, a two-stage circuit with automatic bias was selected. The widths of the transistors were selected taking into account the analysis of the minimum achievable noise figure and the balance between current consumption and output power. The autobias of the first stage is organized using an inductor. This solution allows not only to set the required DC mode, but also ensures input matching of the amplifier. The second stage is covered by negative feedback, which has a positive effect on the stability of the amplifier and its output matching. The amplifier supply voltage is 5 V, while resistors in the DC filter circuits set the required voltage value at the drain of each stage. Based on electrodynamic analysis, a topology was synthesized and an MIC was manufactured in the form of a gallium arsenide crystal 1.8 x 1.8 mm in size and 100 μm thick. An experimental study of manufactured LNA samples showed that in the frequency range from 5 GHz to 10 GHz the noise figure does not exceed 1.2 dB, while the minimum gain in the operating band is 21 dB. Characteristics of the amplifier has good temperature stability. The main parameters of the manufactured microcircuit are at the level of parameters of foreign analogues.

Grounded and floating memristor emulator employing ICCTA: decremental or incremental operation

ABSTRACT This article describes floating and grounded memristor emulator built with an Inverting Current Conveyor Transconductance Amplifier (ICCTA). One ICCTA, one capacitor, and three resistors are used to implement the charge controlled floating memristor emulator. In contrast, a flux controlled grounded memristor emulator consists of one ICCTA, one resistor, and one capacitor. Both presented circuits do not incorporate complex circuits such as analog multiplier circuits, passive inductors, and analog to digital converter circuits in their implementation, which is advantageous in terms of circuit realisation. The designed circuits may be operated in incremental as well as decremental configurations by appropriate setting of MOS switches. In addition, PVT (process, voltage, and temperature) analysis of the proposed memristor is also included. Furthermore, the non-ideal explanation of the proposed circuits is mathematically examined. The proposed emulators are simulated in SPICE simulator using 180 nm technology. Meminductor circuit and memristor-based low pass filter are used to validate the effectiveness of the designed circuits.

Research on Overvoltage Caused by Long Cable of Converter

Abstract Due to the impact of energy crisis and environmental pollution, wind power generation has developed rapidly as a clean and renewable energy source. The direct drive wind power system has attracted the attention of the country and wind power enterprises due to its simple structure and good reliability. This article conducts in-depth analysis on the overvoltage generated at the input end of the converter in the direct drive wind power generation system, and concludes that there are two reasons for the overvoltage: (1) there is a certain stray inductance in the direct drive wind power generation system. When the IGBT inside the converter is turned off too frequently, the induced electromotive force generated at both ends of the converter overlaps with the DC voltage, resulting in overvoltage pulses; (2) The long cable connection between the converter and the generator causes voltage reflection and generates overvoltage at the converter end. Therefore, if not suppressed in a timely manner, it will cause damage to the converter and generator. In order to prevent overvoltage damage, this article designs a new filtering circuit at the input of the converter to suppress overvoltage. A simulation model is built using Matlab simulation software to verify the advantages and disadvantages of the new filtering circuit. Finally, a comparative analysis of its simulation waveform shows that the new filtering circuit effectively suppresses the overvoltage at the input end of the converter, And the low energy consumption and wide filtering range effectively protect the safe operation of the converter.

Dual-band low-power RF-to-DC signal converter circuits for energy harvesting

This article presents dual-band low-power, high-sensitive radio-frequency (RF)-to-direct current (DC) signal converter circuits, operating at 2.45 and 5.5 GHz bands, for radio frequency energy harvesting applications. In particular, it focuses on the lumped element and microstrip transmission line model circuits. The lumped element RF-to-DC converter circuit is composed of a dual-band impedance matching circuit, voltage-doubler rectifier, and DC-pass filter with a resistive load of 5 kΩ. This converter circuit gives a DC output voltage of 48 mV at 2.45 GHz and 25 mV at 5.5 GHz on −25 dBm input power. Maximum conversion efficiency is 47% at the 2.45 GHz band and 27% at the 5.5 GHz band when the input power is set to −10 dBm. Circuit design steps, matching conditions, performance parameters, and so on, are presented using Advanced Design System simulation. To validate the concept of the lumped element model, a microstrip transmission line RF-to-DC converter model is simulated and fabricated. It also composes of a dual-band matching network, voltage-doubler, and DC-pass filter with a load resistance of 5 kΩ. At a low input power of −18 dBm, it gives an output voltage of 21 mV in measurement. An appropriate match between the simulation and measurement is noted.

A parameter design method of LC filter circuit for closed‐loop dynamic power supply system based on linear power amplifier

AbstractThe linear power amplifier (LPA) suffers from low power supply utilization in the DC power supply mode, leading to reduced output efficiency. This paper constructs an efficient power supply mode based on closed‐loop dynamic power supply system (CLDPSs). The CLDPSs can generate a pair of bipolar dynamic power supplies based on a predetermined signal to provide power to LPA, which can maintain a small voltage drop between the power supply and the output of LPA, thereby improving the power supply utilization of LPA. In addition, the study also focuses on the conflicting relationship between the output ripple and the dynamic performance of the CLDPSs, for which a new parametric design of the LC filter circuit is proposed, aiming to achieve a balance between these two aspects. Finally, a voice coil motor driving platform is constructed for experimental testing. The results demonstrate that the output ripple and dynamic performance of the CLDPSs can be balanced. In comparison to the DC power supply mode, the CLDPSs power supply mode can enhance the efficiency of LPA by 2 times while the driving accuracy of voice coil motor is basically unchanged.

Current-mode Universal Filter using Fin type Field Effect Transistor (FinFET) Transistor-Based Multioutput Current Controlled Current Conveyor Transconductance Amplifiers

For single digit nanometric dimensions, the fin type Field Effect Transistor (FinFET) transistor is a promising technology. FinFETs are utilized to reduce power consumption and boost performance since the two gate voltages may be regulated independently or dependently. This work investigates the design of multioutput current-controlled current conveyor transconductance amplifiers, or M.O.C.C.C.C.T.A.s. to carry out all standard operations, such as LP, HP, BS, BP, and AP. One of the circuit's features is its capacity to change the pole frequency electrically and independently by applying the proper input bias currents based on the quality factor. There are merely two grounded capacitors and two M.O.C.C.C.C.T.A.s in the simple circuit design. The recommended design is perfect for further development into an integrated circuit because it only contains grounded components and does not require any external resistors. The FinFET 7 nm PTM-MG model is used in LT-spice to simulate the suggested active filter circuit. The obtained findings are in good agreement with the theoretical prediction.

RANCANG BANGUN PENGENDALI LAMPU DENGAN KOMUNIKASI SERIAL BERBASIS MIKROKONTROLLER PIC16F877 DAN 16F876 MELALUI JARINGAN LISTRIK RUMAH

Serial data transmission can be applied by the use of the grid as a carrier is one alternative that has some advantages, such as reducing the use of cables In this design project created a special application of serial data communication via the electricity network that uses circuit PIC16F877di Microcontroller Master controller as the main controller to control ON / OFF to 5 pieces Slave controller circuit using the PIC16F876 microcontroller to control the lights as the electrical load. Research conducted using a modulation method Frequency Shift Keying (FSK) as modulator and demodulator, also using a series transformer coupling and high pass filter circuit. The main component Frequency Shift Keying (FSK) the Integrated Circuit (IC) XR2206 as a Modulator and Demodulator IC XR2211 as, as well as using a passive filter that serves to pass a predetermined frequency is 70KHz - 80KHz. The frequency value to be achieved by calculating the value of an external capacitor and resistor. The results of the calculations at the design stage modulator, with a value of C = 10nF obtained value R1 = 1428Ω, R2 = 1250Ω. Keywords: PIC16F877, PIC16F876, XR2206, XR2211

A Wideband Circularly Polarized Dipole Antenna with Compact Size and Low-Pass Filtering Response.

This paper presents a compact wideband circularly polarized cross-dipole antenna with a low-pass filter response. It consists of two pairs of folded cross-dipole arms printed separately on both sides of the top substrate, and the two dipole arms on the same surface are connected by an annular phase-shifting delay line to generate circular polarization. A bent metal square ring and four small metal square rings around the cross-dipoles are employed to introduce new resonant frequencies, effectively extending the impedance and axial-ratio bandwidth. Four square patches printed on the middle substrate are connected to the ground plane by the vertical metal plates in order to reduce the antenna height. Thus, a compact wideband circularly polarized antenna is realized. In addition, a transmission zero can be introduced at the upper frequency stopband by the bent metal square rings, without using extra filter circuits. For verification, the proposed model is implemented and tested. The overall size of the model is 90mm×90mm×33mm (0.37λ0×0.37λ0×0.14λ0; λ0 denotes the center operating frequency). The measured impedance bandwidth and 3 dB axial-ratio (AR) bandwidth are 53.3% and 41%, respectively. An upper-band radiation suppression level greater than 15 dB is realized, indicating a good low-pass filter response.