Vertically Coupled Microring Resonator Filter :Versatile Building Block for VLSI Filter Circuits

In this review, the recent progress in the development of vertically coupled micro-ring resonator filters is summarized and the potential applications of the filters leading to the development of VLSI photonics are described.

Digitalization of inverting filter shaping circuit for nuclear pulse signals

In the design of filter shaping circuits for nuclear pulse signals,inverting filter shaping circuits perform better than non-inverting filter shaping circuits.Because these circuits facilitate changing the phase of a pulse signal,they are widely used in processing nuclear pulse signals.In this study,the transfer functions of four types of inverting filter shaping circuits,namely the common inverting filter shaping,improved inverting filter shaping,multiple feedback low-pass filter shaping,and third-order multiple feedback low-pass filter shaping,in the Laplacian domain,are derived.We establish the numerical recursive function models and digitalize the four circuits,obtain the transfer functions in the Z domain,and analyze the filter performance and amplitude-frequency response characteristics in the frequency domain.Based on the actual nuclear pulse signal of the Si-PIN detector,we realize four types of inverting digital shaping.The results show that under the same shaping parameters,the common inverting digital shaping has better amplitude extraction characteristics,the third-order multiple feedback low-pass digital shaping has better noise suppression performance,and the multiple feedback digital shaping takes into account both pulse amplitude extraction and noise suppression performance.

Optimized Implementation for Wave Digital Filter Based Circuit Emulation on FPGA

A binary tree representation is designed in this paper for optimization of wave digital filter（WDF）implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree representation at first.This WDF binary tree can then be transformed to several topologies with the same implication,since the WDF adaptors have a symmetrical behavior on their ports.Because the WDF implementation is related to field programmable gate array（FPGA）resource usage and the cycle time of emulation,choosing aproper binary tree topology for WDF implementation can help balance the complexity and performance quality of an emulation system.Both WDF-FPGA emulation and HSpice simulation on the same circuit are tested.There is no significant difference between these two simulations.However,in terms of time consumption,the WDF-FPGA emulation has an advantage over the other.Our experiment also demonstrates that the optimized WDF-FPGA emulation has an acceptable accuracy and feasibility.

Pspice Equivalent Circuit Model for Implementation of Surface Acoustic Wave Filter

The crystals of quartz,lithium,and piezoelectric ceramics have a piezoelectric effect as their major characteristic.The surface acoustic wave filter(SAWF) was designed by using this property.However,the experimental cost of the fabrication of SAWF is higher than that of mechanical filter or LC filter.Through the RLC(resistor,inductor and capacitor) network equivalent circuit and the interdigital transducer(IDT) equivalent circuit model,the electromotive force,the mechanical impedance of piezoelectric plate,and the wave number of Mason circuit model were researched.The equivalent circuit can be used to reduce product development costs and shorten the development cycle.Comparing simulation result by Pspice software with the theory of SAWF,the simulated waveform is similar to theory measurement,and the equivalent circuit model is verified.

基于MATLAB GUI的交流电路频率特性仿真教学平台设计

为了使学生更加直观地理解交流电路中的频率特性,构建了一种基于MATLAB GUI的交流电路频率特性仿真教学平台。该仿真平台包括RC滤波电路和RLC谐振电路两个模块,其中RC滤波电路能够实现低通滤波、高通滤波和带通滤波电路频率特性的仿真研究,RLC谐振电路能够实现串联谐振和并联谐振电路频率特性的仿真研究。借助该仿真平台,只需手动输入电路元件参数,就能获得各交流电路的幅频和相频特性曲线,最后将源程序封装成.exe文件。该仿真平台操作简单,便于任课教师和学生使用,能够显著地提高课堂教学质量。

Lumped-equivalent circuit model for multi-stage cascaded magnetoelectric dual-tunable bandpass filter

A lumped-equivalent circuit model of a novel magnetoelectric tunable bandpass filter, which is realized in the form of multi-stage cascading between a plurality of magnetoelectric laminates, is established in this paper for convenient analysis.The multi-stage cascaded filter is degraded to the coupling microstrip filter with only one magnetoelectric laminate and then compared with the existing experiment results. The comparison reveals that the insertion loss curves predicted by the degraded circuit model are in good agreement with the experiment results and the predicted results of the electromagnetic field simulation, thus the validity of the model is verified. The model is then degraded to the two-stage cascaded magnetoelectric filter with two magnetoelectric laminates. It is revealed that if the applied external bias magnetic or electric fields on the two magnetoelectric laminates are identical, then the passband of the filter will drift under the changed external field; that is to say, the filter has the characteristics of external magnetic field tunability and electric field tunability. If the applied external bias magnetic or electric fields on two magnetoelectric laminates are different, then the passband will disappear so that the switching characteristic is achieved. When the same magnetic fields are applied to the laminates, the passband bandwidth of the two-stage cascaded magnetoelectric filter with two magnetoelectric laminates becomes nearly doubled in comparison with the passband filter which contains only one magnetoelectric laminate. The bandpass effect is also improved obviously. This research will provide a theoretical basis for the design, preparation, and application of a new high performance magnetoelectric tunable microwave device.

基于DKF-Bi-LSTM的阀控式铅酸电池SOC在线估计方法

精准估计阀控式铅酸蓄电池的荷电状态(SOC)对变电站直流系统的可靠性和安全性有着重要的作用,为提高SOC估算精度,提出一种基于DKF-Bi-LSTM的铅酸蓄电池SOC在线估计方法,基于二级结构的双卡尔曼滤波算法,分别进行模型估计和状态估计。通过卡尔曼滤波算法对模型参数进行动态跟踪,进而基于扩展卡尔曼滤波算法在线估算电池SOC值。将在线估算结果、电流、电压、温度值作为Bi-LSTM神经网络的输入,电池SOC预测值作为网络输出,实现对电池SOC的在线估计。经测试发现,与DKF和Bi-LSTM算法相比,DKF-Bi-LSTM算法的SOC预测均方根误差更小,其SOC在线估计方法具有更高的准确性。

直流换流站高通HP3型交流滤波器电抗器匝间故障监测及保护

直流换流站高通HP3型交流滤波器组中电抗器匝间短路故障事故多发,由于缺乏对此故障的快速监测及保护,导致其匝间短路持续存在3~9 min之久并起火燃烧。匝间短路后电抗器的等值电感会不断减小,由此引起了滤波器电路参数变化并进而引发了滤波器配置的热过负荷保护启动告警,长久故障也引发了次生的电抗器底部支撑绝缘子闪络接地致使滤波器差动保护动作出口跳闸。文中分析了3起典型故障案例,结合C型高通HP3型滤波器电路设计理念及运行特点,解释了有关保护启动及动作的原因。基于匝间短路会导致HP3电路中电阻器上的工频电压、电流会随着匝间短路的不断发展而剧烈增大的特性,提出了一种基于工频电压差动原理的故障监测及保护方法。

中压并联型DVR链式变流器主电路及参数设计

中压并联型动态电压恢复器(DVR)由快速开关(HSS)和并联电压源变流器组成。电网发生故障时HSS关断,并联变流器转入负荷电压控制运行模式,并联变流器内置的超级电容器向负荷释放能量。此处对并联链式变流器主电路进行分析与比较,设计了链式变流器功率模块直流侧滤波电路,给出了滤波电路参数设计方法,并通过仿真和实验验证了直流侧滤波电路滤波效果,给出了链式变流器并网运行实验结果。

基于混合二极管的Sallen-Key低通滤波电路振荡行为研究

设计一种基于混合二极管的Sallen-Key低通滤波振荡电路,将PN结型二极管与电感、电容串并联组合所构成的混合二极管接入低通滤波电路的输入端,构建一种具有复杂动力学行为的混沌振荡电路.引入不对称系数来模拟实际电路中二极管元件之间电学特性的偏差,通过特定参数的相轨迹图、分岔图和Lyapunov指数谱对振荡电路的对称、不对称系数下两种振荡状态进行数值分析.实验产生振荡电路中独特的吸引子共存现象,揭示了受电路参数调节的对称、不对称共存分岔、反单调特性等丰富的动力学行为演化过程.最后,基于FPGA技术完成振荡电路的数字电路实验,验证了数值仿真的正确性和物理可实现性.

Electromagnetic Analysis and Optimization of High-speed Maglev Linear Synchronous Motor Based on Field-circuit Coupling

High speed maglev train has become a new non-contact transportation mode mainly studied in recent years because of its non-sticking and high speed characteristics.Firstly,the finite element model of the long stator linear synchronous motor(LSM)is established based on the structure of the test prototype.After calculation,it is compared with the experimental data and verified.On this basis,a field-circuit coupling model based on inverter circuit is established,and the influence of carrier wave ratio change on the output characteristics of LSM is calculated and analyzed.Finally,the filter circuit is introduced into the field-circuit coupling model,and the influence of the filter circuit on the output characteristics of the LSM is compared and analyzed.

基于FPGA的R2R DAC设计与仿真

随着通信技术和数字信号处理技术的快速发展,对数模转换器(DAC)提出了更高的要求,尤其在转换速度和转换精度方面,为此,设计了一种高精度的数字DAC系统。该系统包括DAC模块、电源电路和模拟滤波模块。其中,DAC电路设计是基于R2R电阻网络的架构,使用分立元器件设计的一种16位高性能数模转换器。输入端采用的是I2S通信接口,将输入的串行数据转为并行数据,再传输至电阻网络,经过DAC完成数模转换。通过设计的模拟滤波器对输出的模拟信号进行滤波处理,可使整个系统满足高精度和高分辨率的要求。最后,使用FPGA测试和验证该系统,发现数据转换结果达到了预期目标。

AFS型测流平台水文信号采集方案的研究应用

为了实现无人远程测流,需要采集三个关键信号,即水面信号、流速信号、水底信号,这里提出了一种关键水文信号采集方案,通过旋桨流速仪和使用STM32单片机的信号采集仪来采集水面信号和流速信号;通过编码器与转臂式失重开关采集水底信号;PLC计算出水深与流速信号后传输至上位机做保存与处理。流速信号受制于旋桨流速仪影响,抖动干扰严重,提出了去抖动滤波方案,并通过实验验证滤波电路切实可行;针对不同地区水阻所造成的A/D采集参考电压不同,编写了专用APP,采用蓝牙连接调整参数,提高了该采集方案的适用性。经过实地测试,使用该方案所得到的流速、水深数据符合水文站的精度要求,能够有效的节省人力成本和时间成本,提高水文测流过程的自动化程度。

半航空电磁接收系统的设计与应用

利用半航空电磁法进行勘探时,半航空电磁接收系统中线圈传感器获取的电压信号很小且易受噪声等因素干扰,无法直接采样和分析。针对上述问题,设计了一套新型的低噪声半航空电磁接收系统。该系统以双通道匹配晶体管MAT03、MAT12和低噪声放大器AD8429为核心设计了低噪声放大电路,以运算放大器NE5532为核心设计了五阶低通滤波电路。通过仿真验证了设计电路功能的可行性,并对其进行了性能测试和野外试验。测试和试验结果表明:所设计的放大电路增益可调且噪声低于市面上的放大器,低通滤波电路抑制高频干扰效果良好。

锂电池低压逆变器前级升压设计

目前国内在低压逆变器方面的研究与工程应用相对较少,设计一台输出220 V、50 Hz稳定正弦波的锂电池低压逆变器,需要克服前级低压到400 V升压过程中出现的电路纹波过大、电流过大以及器件散热等问题。在电压变换电路、升压主电路和控制电路上,通过优化电路拓扑结构和PCB布线,辅助电源的纹波降低了23.1 mV;结合元器件的选择和研究,提出一种适用于锂电池低压逆变器的前级升压方案,通过调节反馈电路,将3.2 V的电压稳定地升压至400 V,用于3.2 V低压逆变器实物中。该设计方法对其他低压逆变的研究和应用具有一定的借鉴意义。

一二次融合设备ECVT信号处理电路仿真与研究

针对电容分压式电子式电压互感器在一二次融合设备中输出的二次电压信号微弱、容易受到高次谐波干扰、信号传输不稳定等问题,提出了一种基于Sallen-Key型的高阶高精度滤波器来抑制谐波,减少对工作信号的干扰。首先对互感器的工作原理进行了分析,然后基于该原理和一二次融合设备的工作频带,结合Matlab/Simulink仿真软件对积分电路和滤波电路进行研究设计,最后对滤波电路环节进行优化,对整体电路进行仿真。结果表明,优化后的电路能够更有效地抑制高次谐波的干扰,保证基波稳定输出。

基于文氏桥振荡器的CCCⅡ带通滤波器

为了得到一个最简单、最经济的电流模式高Q带通滤波器,根据传统的文氏桥振荡器和伴随网络理论,设计了一个电流模式/跨导模式的CCCⅡ带通滤波器。通过调整CCCⅡ的偏置电流,电路的极点频率和品质因数能够被独立地电调谐,当满足IB3=2IB4,电路还能产生正弦振荡。由于电路使用4个CCCⅡ和2个接地电容,因此电路适宜集成。计算机仿真结果表明设计方法正确。

基于卡尔曼滤波的动力电池SOC估算

由于传统无迹卡尔曼滤波估算方法具有局限性,为了能准确估算动力电池荷电状态(state of charge,SOC),提出了一种基于无迹卡尔曼粒子滤波的动力电池SOC估算方法.以三元锂电池为研究对象,建立了电池二阶RC等效电路模型,通过对电池进行充放电试验辨识出模型参数,并验证模型准确性.采集了实际工况下的电池数据,分别用无迹卡尔曼滤波算法、粒子滤波算法和无迹卡尔曼粒子滤波算法估算电池SOC,在MATLAB中进行了仿真试验,并对估算的电池SOC进行比较.结果表明:无迹卡尔曼粒子滤波算法可以快速准确地估算出电池SOC,误差小于2.5%,优于另外2种算法.

一种低噪声水声信号电路设计

文章主要介绍一种水听器信号处理电路,主要包括前放电路、四阶带通滤波电路以及放大电路。该电路采用ADI公司的低噪声、低功耗的AD8605和AD8608芯片,该电路的增益为60 dB,滤波带宽为200 Hz,等效电容输入噪声低。通过对水声信号进行放大和滤波,能够有效地从噪声信号中提取出目标信号。

基于泰勒公式的单相桥式整流滤波电路分析

单相桥式整流滤波电路输出电压波形难以用解析式来描述,输出电压波形中,每个周期有一个输出电压下降的时间段。该时间段的长短与滤波电容和负载电阻的数值有关。通过对电路工作过程进行分析,得到相关物理量的数学函数关系式,通过泰勒公式对关系式进行近似简化分析,可以得到电压下降时间段时长与时间参数RC之间的关系式。根据关系式计算得到的数据与电路仿真数据较为接近。关系式可以用于电容值的选取、电压下降时间段时长的计算。