手机中的滤波器

手机中的滤波器种类繁多，有分离元件滤波，也有组合滤波器进行滤波或其它形式元件滤波。其中，滤波器也是由R、L、C元件或等效电路构成，可以起到分离信号，滤除杂波、抑制干扰、阻抗变换与匹配等作用。手机中如需要衰减性很小的滤波器，利用普通L、C来滤波会使电路复杂，而且会导致射频性能变     

利用元件寄生特性改善DAC重建滤波器性能

本文在设计DDS系统的DAC输出重建滤波器的基础上,分析比较了元件的寄生特性对滤波器阶数和性能的影响之后,提出了对电路的改进方法.经过软件仿真对元件值进行重新修改后,通过采用不同PCB板布局的设计进行了硬件测试,证明了该改进方法的正确性.     

高频有源滤波器的实用设计

本文给出了高频有源滤波器的实用设计方法。根据给定的技术指标，首先设计一个基于运算放大器的RC有源原形滤波器，然后根据网络理论，将其转换成基于电流传输器（CCⅡ－）的RC有源滤波器。由于两个滤波器具有相同的传输函数以及相同的元件值，因此，基于CCⅡ－的滤波器保留了原形滤波器的优良性能。文中给出了用AD844实现的滤波器电路以及计算机模拟结果。     

RC有源滤波器在电力线载波机中的应用

ＲＣ有源滤波器在电力线载波机中的应用国营七三四厂通讯技术研究所黄秋余近年来，随着电力线载波通信设备的小型化，ＲＣ有源滤波器已为人们所重视。由于音频应用的ＬＣ滤波器体积大。Ｑ值低、价格高，而且不能用厚膜和薄厚的技术来集成，所以人们把可以取消笨重电感的Ｒ...     

低损耗多调谐无源滤波器

双调谐滤波器和三调谐滤波器具有占地少、减少高压电感和电容元件、节省开关等诸多优点,已经在直流输电工程中得到广泛应用。但是现有的多调谐阻尼型滤波器用于低次谐波滤波时,滤波器的基波损耗过大。文中介绍了一种低损耗的阻尼型双调谐滤波器和三调谐滤波器电路,其基本思路是使滤波电路的部分LC元件构成基波串联调谐电路,并使并联阻尼电阻连接在基波调谐电路的两端,从而避免阻尼电阻上的基波功率损耗。新滤波器用在高压直流输电系统中将节省运行成本。     

一种新颖的基于电流传送器的三输入单输出多功能滤波器

文中提出了一种采用电流传送器ＣＣⅡ＋／－构成的电流模式三输入、单输出多功能滤波器，该滤波器仅使用三个ＣＣⅡ＋／－器件，３个接地电阻和３个接地电容，选择电路三个输入端中不同的输入信号组合，即可在输出端得到低通、高通、带通、陷波和全通五种基本的二阶滤波功能。比ＣＨＡＮＧＣ．Ｍ．和ＣＨＥＮＰ．Ｃ．所提电路简单。该电路不仅ω－和Ｑ值可调，而且具有低的无源灵敏度。     

有源滤波器在继电器保护中的应用分析

主要介绍了有源带通滤波器和有源带阻滤波器的两个典型电路。通过数学模型对电路进行分析,从而得出有源带通滤波器和有源带阻滤波器的设计方法和调试方法。     

中心频率可连续调节带通滤波器设计

文中介绍了以ＭＡＸ２６４为核心构成的开关电容带通滤波器实用电路。通过引脚编程,可任意改变ｆ０及Ｑ值,实现中心频率的连续调节和数字显示,具有性能好,精度高,电路简单,调整容易等特点。     

宽调谐高线性超短波电调滤波器的设计与实现

为减小多通道接收机中预选滤波器的体积,并提高其扫描滤波的精准性,依据电调滤波器技术具有连续调谐选通的特点,对电路结构进行优化,即增加耦合元件、变换耦合模式、引入阻抗变换,同时进行仿真分析,设计了一种插入损耗小、调谐范围宽、选择性高的电调滤波器电路机构来替代传统的亚倍频程滤波器。     

低频有源滤波器设计中浮地阻抗的模拟

本文提出了模拟浮地电感、电容和FDNR元件的新电路,此电路容易设计和调整,它可实现阻抗模拟并且有高元件值,从而特别适用于低频有源滤波器。     

高阶椭圆滤波器的设计与仿真

分析信号频谱时为了提高系统的频率分辨率,需要设计性能优良的模拟滤波器.在所有的模拟滤波器中,椭圆滤波器有着极高的性能,但其传统设计方法过于复杂.本文介绍了椭圆滤波器VCVS(压控电压源)的结构,研究了一种通用的VCVS电路综合方法及元件值计算公式.利用MATLAB设计低通椭圆滤波器传递函数,成功综合出一款高性能七阶椭圆低通滤波器,EDA(电子设计自动化)软件OrCAD/PSpice10.5仿真和实际测试表明,其性能指标完全达到设计要求.     

Filters and components with inductance cancellation

Electrical filters are important for attenuating electrical ripple, eliminating electromagnetic interference (EMI) and susceptibility, improving power quality, and minimizing electromagnetic signature. Capacitors are critical elements in such filters, and filter performance is strongly influenced by the capacitor parasitics. This paper introduces a new design technique that overcomes the capacitor parasitic inductance that limits filter performance at high frequencies. Coupled magnetic windings are employed to effectively cancel the parasitic inductance of capacitors, and to add inductance in filter branches where it is desired. The underlying basis of the new technique is treated in detail, and its application to the design of both discrete filters and integrated LC filter components is described. Numerous experimental results demonstrating the high performance of the approach in both discrete filters and integrated filter elements are provided.     

温度对移动颗粒层过滤高温除尘性能影响的研究

研究温度对移动颗粒层过滤高温除尘性能的影响规律，首次提出温度与捕集比的理论关系式，并进行了实验验证，得到了移动颗粒层在高温状态下进行过滤除尘的实验结果，为移动 过滤高温除尘工艺的放大和工程化打下了基础。     

Problems in creation of modern air inlet filters of power gas turbine plants in Russia and methods of their solving

The main problems in creation and operation of modern air inlet paths of gas turbine plants installed as part of combined-cycle plants in Russia are presented. It is noted that design features of air inlet filters shall be formed at the stage of the technical assignment not only considering the requirements of gas turbine plant manufacturer but also climatic conditions, local atmospheric air dustiness, and a number of other factors. The recommendations on completing of filtration system for air inlet filter of power gas turbine plants depending on the facility location are given, specific defects in design and experience in operation of imported air inlet paths are analyzed, and influence of cycle air preparation quality for gas turbine plant on value of operating expenses and cost of repair works is noted. Air treatment equipment of various manufacturers, influence of aerodynamic characteristics on operation of air inlet filters, features of filtration system operation, anti-icing system, weather canopies, and other elements of air inlet paths are considered. It is shown that nonuniformity of air flow velocity fields in clean air chamber has a negative effect on capacity and aerodynamic resistance of air inlet filter. Besides, the necessity in installation of a sufficient number of differential pressure transmitters allowing controlling state of each treatment stage not being limited to one measurement of total differential pressure in the filtration system is noted in the article. According to the results of the analysis trends and methods for modernization of available equipment for air inlet path, the importance of creation and implementation of new technologies for manufacturing of filtering elements on sites of Russia within the limits of import substitution are given, and measures on reliability improvement and energy efficiency for air inlet filter are considered.     

Low-complexity distributed parallel processor for 2D IIR broadband beam plane-wave filters

Real-time systolic-array-based implementations of VLSI two-dimensional (2D) infinite-impulse-response (IIR) frequency-planar beam plane-wave filters have potentially wide applications in the filtering of spatio-temporal RF broadband plane waves based on their directions of arrival (DOAs). Distributed-parallel-processor (DPP) implementations of the systolic arrays allow synchronous sampling of the 2D input signal array, but because of the direct-form structure they have high circuit complexity. To address the high-complexity problem, the differential-form 2D z-domain transfer function is employed here to obtain a novel DPP systolic-array-based filter architecture. Differential operators are obtained by applying elemental predistortion to the passive LR prototype filter network using series-connected negative-resistance elements. The proposed systolic 2D IIR architecture is implemented on a single Xilinx Virtex-4 Xc4v Sx35-10ff668 FPGA chip. Two examples of broadband plane-wave filtering supporting N = 32 and N = 64 sensors are reported. On-chip test results are achieved using stable real-time tests at frame sample frequencies of up to 90MHz as well as stepped hardware cosimulation in conjunction with a parallel-operating MATLAB/Simulink simulation.     

Active-passive power circuit

The recent development of a semiconductor device technology realizes small-size, lightweight, high performance power switching devices. However, reactive elements such as an inductor or a PWM inverter achieves high-performance current control, which is applied to the active filter, and so on [2, 4]. If a compact and high efficient reactive component is developed, the power converter technology may drastically change the application field. In this paper, the concept of variable active-passive reactance (VAPAR) which consists of an inverter and passive elements is proposed. The VAPAR behaves like a two-terminal reactive element and the produced active reactance component works as a passive reactive component, including in transient state. The principle of VAPAR and two possible control schemes to realize VAPAR are realized. Through simulations and experiments, it is verified that VAPAR shows reactive characteristics not only in steady state, but also in transient state, as proposed, and basic characteristics of both control schemes are clarified.     

数学形态学算子在电力系统突变信号检测中应用

数学形态学是一种非线性图象(信号)处理和分析工具,对信号特征的提取完全在时域中进行,信号的相位移和幅值特征不会变化。详细介绍了一维情况下灰度形态变换、形态学算子构造的滤波器和提取暂态突变特征等。应用电力系统暂态仿真软件PSCAD/EMTDC,仿真结果表明,在选择合适结构元素的条件下,数学形态算子有很好的滤波功能,对突变信号的检测具有速度快、时延小、易于分辨等特点。     

全封闭集中式特高压设备绝缘油处理系统

基于传统"敞开式"滤油方法,提出了一种全封闭集中式绝缘油处理方法,并设计开发了相应的滤油系统。该系统把真空滤油机、压力式滤油机、油罐和变压器或高抗等通过高性能油管组合在一起,通过油路的切换实现各种滤油功能,解决了特高压变电站大型油浸设备对绝缘油品质要求高、油量大不易处理的问题。通过1 000 kV南阳开关站高抗绝缘油滤油的实践检验,证明该滤油方法和滤油系统是可行的,并且具有较高的效率。     

用于电能计量芯片的无功功率计量方法

现有电能计量芯片中无功功率计量电路难以同时满足计量精度高与硬件开销小的要求。为解决此问题,提出了一种无功功率计量的新方法,该方法采用3个一阶IIR滤波器,其中电压通道内的相位移动滤波器使电压信号产生-90°相移,电压通道和电流通道内的两个幅度补偿滤波器共同对由相位移动滤波器产生的信号幅度衰减进行补偿。两个幅度补偿滤波器被要求设计成具有相同的结构和参数,二者的并联应用不会改变电压与电流之间的相位差。提出了高效的无功功率计量系统设计方法,其中特别是幅度补偿滤波器设计的优化方法。仿真和实际产品测试结果表明,该无功功率计量方法不仅硬件资源消耗较少,而且可以达到较高的计量精度,优于现有电能计量芯片的无功功率计量方法。     

跳频滤波器自动测试系统设计

为了提高跳频滤波器的测试效率,设计了基于C++ Builder的自动测试系统;在介绍跳频滤波器基本原理的基础上,描述了自动测试系统的硬件平台组成及软件功能架构,通过解决数据处理和数据正确采集等关键问题,实现了跳频滤波器测试过程中测量、数据采集、筛选等软件功能,并完成了简单友好的操作界面设计.经过实际跳频滤波器测试验证,...