The Line Shape of Double-Sided Tooth-Disk Waveguide Filters Based on Plasmon-Induced Transparency

We numerically investigate a coupled-resonator structure consisting of a stub resonator and a nanodisk resonator using a two-dimensional finite element method. Simulation results show that plasmon-induced transparency （PIT） occurs in the transmission spectra, and the sharp asymmetric Fano lines increase the sensitivity to 1.4 ×10^3 nm/RIU. We also analyze the properties of the structure with different radii of the nanodisk and the length of the tooth cavity. Moreover, we find that the PIP only happens when the staggered system is around a fixed location with different separate distances, which is not similar to the previous researches. Our model may be important to photonic-integrated circuits and the sensitivity in sensors.

Multiple Kalman filters model with shaping filter GPS real-time deformation analysis

In order to detect the deformation in real-time of the GPS time series and improve its reliability, the multiple Kalman filters model with shaping filter was proposed. Two problems were solved: firstly, because the GPS real-time deformation series with a high sampling rate contain coloured noise, the multiple Kalman filter model requires the white noise, and the multiple Kalman filters model is augmented by a shaping filter in order to reduce the colored noise; secondly, the multiple Kalman filters model with shaping filter can detect the deformation epoch in real-time and improve the quality of GPS measurements for the real-time deformation applications. Based on the comparisons of the applications in different GPS time series with different models, the advantages of the proposed model were illustrated. The proposed model can reduce the colored noise, detect the smaller changes, and improve the precision of the detected deformation epoch.

基于Shape Context的形状匹配方法的改进

传统的Shape Context算法只对简单的形状进行形状匹配.关注于人脸形状匹配和智能化视频监控应用,提出一种Shape Context形状匹配的改进方法,并将Shape Context的形状匹配运用到人脸的形状匹配中.本方法基于Shape Context算法,使用改进的边界提取算法,并融入了扩散滤波的预处理算法和数学归一化方法.本方法适用简单形状和人脸形状匹配,具有二维不变性,并且在智能视频监控中能得到稳定和有效的使用.

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.

Synthesis of Fractional-order PI Controllers and Fractional-order Filters for Industrial Electrical Drives

This paper introduces an electrical drives control architecture combining a fractional-order controller and a setpoint pre-filter. The former is based on a fractional-order proportional-integral(PI) unit, with a non-integer order integral action, while the latter can be of integer or non-integer type. To satisfy robustness and dynamic performance specifications, the feedback controller is designed by a loop-shaping technique in the frequency domain. In particular, optimality of the feedback system is pursued to achieve input-output tracking. The setpoint pre-filter is designed by a dynamic inversion technique minimizing the difference between the ideal synthesized command signal(i.e., a smooth monotonic response) and the prefilter step response. Experimental tests validate the methodology and compare the performance of the proposed architecture with well-established control schemes that employ the classical PIbased symmetrical optimum method with a smoothing pre-filter.

Optimal parameter choice of CR–RC^m digital filter in nuclear pulse processing

CR–RCm filters are widely used in nuclear energy spectrum measurement systems. The choice of parameters of a CR–RCm digital filter directly affects its performance in terms of energy resolution and pulse count rate in digital nuclear spectrometer systems. A numerical recursive model of a CR differential circuit and RC integration circuit is derived, which shows that the shaping result of CR–RCm is determined by the adjustment parameter (k, it determines the shaping time of the shaper) and the integral number (m). Furthermore, the amplitude– frequency response of CR–RC^m is analyzed, which shows that it is a bandpass filter;the larger the shaping parameters (k and m), the narrower is the frequency band. CR–RC^m digital Gaussian shaping is performed on the actual sampled nuclear pulse signal under different shaping parameters. The energy spectrum of 137Cs is measured based on the LaBr3(Ce) detector under different parameters. The results show that the larger the shaping parameters (m and k), the closer the shaping result is to Gaussian shape, the wider is the shaped pulse, the higher is the energy resolution, and the lower is the pulse count rate. For the same batch of pulse signals, the energy resolution is increased from 3.8 to 3.5%, and the full energy peak area is reduced from 7815 to 6503. Thus, the optimal shaping parameters are m -3 and k -0.95. These research results can provide a design reference for the development of digital nuclear spectrometer measurement systems.

P^2: a robust and rotationally invariant shape descriptor with applications to mesh saliency

This work presents a robust and rotationally invariant shape descriptor, namely perception pronouncement （called p2）, to mathematically model the eye fixations, p2 takes two criteria - the local consideration of surface curvature and the global consideration of view- independent visibility - into account. Differing from existing works that often computed the intrinsic surface property of visibility in imaging space, a novel approach is proposed to approxi- mate the attribute in object space using Gauss map and Ray tracing. With the presented shape descriptor, mesh saliency detection, which refers to reasoning about which regions or points of a surface axe important, is more sensible, especially when 3D models fall into two categories： （1） the models possess significant interior/exterior structures; （2） the models contain regions where the contrast in visibility is high. For the models that are out of the categories, saliencies achieved by our approach are comparable to or even better than those of state-of-the-axt methods.

Disturbance Observer Design with a Bode’s Ideal Filter for Sigma-Delta Modulators

It is usually difficult to design a high performance Sigma⁃Delta(ΣΔ)modulator due to system noises.In this paper,a disturbance observer(DOB)is utilized to estimate the system noises and eliminate their effects on ΣΔ modulators.The applied DOB is introduced with a Bode's ideal cut⁃off(BICO)filter used for the Q⁃filter.The proposed DOB with the BICO filter used in ΣΔ modulators can achieve better noise⁃shaping ability,resulting from the less phase loss of the BICO filter.Finally,the simulation results show that the proposed BICO filter scheme is a useful additional tool for improving the performance of ΣΔ modulators.

面向低轨卫星的低资源大带宽自适应成形滤波设计

由于低轨卫星通信过程中信号电平动态变化较大,为了提高信道利用率系统需要根据通信链路情况自动控制传输速率。为保证系统通信不中断,满足实时通信的需求,提出了一种面向低轨卫星的低资源大带宽新型成形滤波器设计方法,该方法采用并行多相级联积分梳状(Cascade Integrator Comb, CIC)滤波器的方式设计成形滤波器,能够实现几百kHz至几百MHz大带宽信号的成形,解决高、中、低速信号自适应连续成形滤波问题。相比传统成形滤波器的高速信号处理能力提高了8倍,能节省乘法器资源95%以上,适应低轨卫星通信场景下星载处理使用。仿真结果表明该滤波器对信号的成形效果和带外抑制情况与传统滤波器几乎一致。

便携式数字多道脉冲幅度分析器的设计

为便于野外测试,设计了一款便携式的数字多道脉冲幅度分析器。采用ARM+FPGA的设计方案,通过嵌入式Linux系统实现控制和用户交互。脉冲信号经调理电路处理后,由采样电路转为数字信号,并在FPGA中完成滤波成形等数字处理,最终由嵌入式系统处理并显示能谱图。采用银粉样品测试,全能峰处能量分辨率为2.80%,道址漂移在2个道址以内,能够满足设计要求。

基于阶梯阻抗谐振器的双频宽带滤波功分器

为了更好地满足无线通信系统对多功能、多频段射频前端器件的要求,提出了一种基于阶梯阻抗谐振器的双频宽带滤波功率分配器。首先,使用单个T形谐振器实现双频滤波单元,同时采用阶梯阻抗技术引入了单独可调的高次模用于展宽双频功分器的高频通带带宽;其次,利用枝节加载技术实现额外谐振模式的引入,展宽了双频滤波功分器低频通带带宽;为了实现小型化设计,对部分微带线进行弯折,使得整个电路结构更加紧凑。此外,利用T形谐振器自身的滤波特性和在微带馈线上加载的开路枝节,在带外产生四个可控的传输零点,提高了通带外选择性;通过在微带馈线上加载扇形枝节和在输出端口引入隔离电阻,有效改善了滤波功分器的带内阻抗匹配效果和隔离度。为了进一步验证,对所提出的滤波功分器进行了加工和测试。该滤波功分器的中心频率为2.83 GHz和4.87 GHz,相对带宽分别为10.6%和11.7%,通带隔离度均大于14.5 dB。测试和仿真结果基本一致。

A new type of inferior vena cava filter and its animal experiment

This article explains the definition of pulmonary embolism as well as its causes and elaborates on a new type of inferior vena cava filter(VCF)we have developed. Shaped like a waistdrum, the VCF is mainly made of TiNi shape memory alloy-wire. It has a subulate wire frame which can intercept the thrombus on each side. Its medial body is made up of straight shape memory alloy-wire . Every pillar is bound by several shape memory alloy springs. This type of inferior vena cava filter has a good resistance to fatigue and is hard to be broken. Through animal experiments its framework has been proved to be lasting. Neither deformation nor fragmentation happened when the VCF had been kept in the body for a long time. The thrombus interception efficiency of our VCF is higher than imported VCFs. The filter is unfavorable for thrombosis. After implantation, the IVC was completely unimpeded and no displacement occurred. Moreover the VCF did little damage to the Wall of vein. Neither IVC perforation nor haematoma occurred after the operation.

基于环形多模谐振器的双频滤波功分器设计

本文设计了一种基于环形多模谐振器的零点可控双频滤波功分器。通过微扰加载,实现双频滤波器功能;利用枝节加载,提高了带宽和带外选择性;采用融合设计方法,将该滤波器与功分器进行集成,完成双频滤波功分器设计;通过在输出端口间引入电阻,提高端口间隔离度。为了验证设计的正确性,设计、加工和测试了该功分器,实测结果和仿真结果基本吻合,当功分器S_(11)<-10 dB时,工作频段分别为2.14~2.52 GHz和4.54~4.84 GHz,端口间隔离度最大达到45 dB。

基于PCA-XGBoost算法的哑铃状SIR差分滤波器设计

随着多业务无线通信技术的发展,具有共模抑制能力的差分带通滤波器越来越受到人们的关注,但是设计差分微带滤波器的传统方法过程复杂且耗时较长。针对这些问题,结合非线性赋权的极限梯度提升(eXtreme Gradient Boosting,XGBoost)算法,通过训练和学习滤波器结构参数和相应频率响应S参数的关系辅助进行滤波器的设计,设计了一款基于改进阶跃阻抗谐振器(Stepped Impedance Resonator,SIR)的哑铃状差分带通滤波器。该滤波器的中心频率为2.6 GHz,相对带宽为7.3%,通带内插入损耗优于0.95 dB,回波损耗优于20 dB,通带内共模抑制优于42 dB,并且具有较宽的阻带。实物测试结果与算法预测结果的一致性,验证了PCA-XGBoost算法(Principal Component Analysis,PCA)用于滤波器辅助设计的可行性。

基于神经网络的椭圆扩展目标形态估计

针对复杂环境下由稀疏量测引起的椭圆扩展目标形态估计精度低的问题,提出了一种基于神经网络的形态估计方法。利用神经网络对目标量测进行处理,估计出椭圆扩展目标的轴长,然后结合卡尔曼滤波算法实现目标的跟踪。仿真实验结果表明,通过与基于随机矩阵、乘性误差以及卷积神经网络等模型的算法相比,所提算法的跟踪性能有显著改进。

双面镀膜法制备高面形精度滤光片

对双面镀膜法制备高面形精度滤光器件进行研究,通过在一面沉积带通滤光膜,另外一面沉积应力/形变匹配膜层的方式,制备了外径Φ25 mm,径厚比为10∶1的HWB900基底高面形精度带通滤光膜。测试结果显示:在通带1 215 nm~1 265 nm波段的平均透过率■≥92%,截止带900 nm~1 135 nm、1 345 nm~1 700 nm内透过率■<1%,镀膜后零件2个表面的均方根(root-mean-square,RMS)值均优于λ/20。深入分析双面镀膜时2个表面面形的变化规律,确定了匹配膜层的厚度及该方法的使用特点。该方法实践性强,制备的光学器件光学性能优异,面形精度高,对高面形精度光学器件的制备具有重要参考价值和指导意义。

基于逆全极点滤波器的高频PWM噪声整形方法

高频开关功率放大器具有高功率、低纹波、高响应的优点,是高加速、高精度定位系统的核心部件。为了解决高频PWM中开关频率与占空比分辨率的矛盾,该文分析调制中噪声整形的基本原理,采用误差反馈结构提取PWM量化噪声进行数字整形,阐述噪声整形滤波器设计约束条件。提出通过逆全极点无限脉冲响应(IIR)滤波器获得有限脉冲响应(FIR)噪声整形滤波器的简明设计方法,仿真及实验表明,该文提出的方法可利用低阶FIR整形滤波器获得平坦的通带和高整形衰减。在不足9位的PWM中,4阶的FIR噪声整形滤波器能够恢复调制信号在10 kHz频段内约40 dB的信噪比损失。

某电厂1000MW超超临界机组给水加氧异常原因分析

某1000MW超超临界机组在给水加氧出现了省煤器入口溶解氧异常降低的现象。通过排查机组运行日志、加氧系统、水汽品质和取样系统,结果表明:给水取样系统在高负荷下的加氧转化不完全,引起氧的消耗量增大,导致省煤器入口溶解氧降低。高温取样架运行排污过程中,高温、高压、高流速样水经过未完全钝化的Y型过滤器滤网,表面的钝化膜发生部分脱落,再度修复引起氧的消耗量增大,造成省煤器入口溶解氧降低。

基于DGS的紧凑型低通滤波器

文中提出一种基于缺陷地结构的新型低通滤波器。其由位于微带结构顶部的加宽微带线、位于接地层中的经典哑铃型缺陷地结构(DGS)和蛇形缝隙缺陷地结构(DGS)组成,结构设计紧凑,容易调整。文中选用0.01 dB等波纹的切比雪夫型低通滤波器,分别采用哑铃型DGS、蛇形缝隙DGS替换LPF原型电路中的电感,加宽微带线替换并联电容,同时将加宽微带线产生的寄生电感考虑进去。哑铃型DGS产生的高频衰减点加宽阻带,蛇形缝隙DGS提供的低频衰减点使得通带到阻带陡峭过渡。实验结果表明,所设计的截止频率为2.54 GHz的低通滤波器具有明显的截止频率响应,通带内插损均在0.9dB以下,阻带抑制均在21dB以下。经实物加工测试验证,所设计的低通滤波器实际结果与仿真结果基本一致,具有可行性。

一种用于射频前端的谐波整形低功耗N通道滤波器

针对传统射频前端N通道滤波器功耗高,不能根据应用要求选择通过或抑制信号的高次谐波等问题,设计了一款谐波整形低功耗N通道滤波器。该滤波器通过添加具有适当权重的额外路径,可实现谐波抑制和整形的功能。同时,将本振Local Oscillator(LO)信号的n次谐波信号作为时钟信号,降低LO信号频率,时钟信号发生器的动态功耗降低到原来的1/n。SMIC 180 nm CMOS工艺的后仿真结果表明,10通道带通滤波器的中心频率在0.1~6.0 GHz可调,增益为0~5 dB,噪声系数小于4.6 dB,功耗为3.5~6.0 mW,输入三阶交调点(Input 3rd-order Intermodulation Point,IIP3)大于10 dBm,3次和5次谐波抑制分别大于65、90 dB,表明该滤波器具有谐波抑制和谐波整形的功能,且具有较低的功耗。