基于开关电容滤波器LTC1064的BPF设计

介绍了一种在2 kHz固定带宽条件下,中心频率可在0.5～100 kHz范围内调节的8阶椭圆带通滤波器的设计方法,采用2片LTC1064开关电容滤波器模块分别构成8阶椭圆高通和低通滤波器,然后两者级联构成带通滤波器,利用FPGA生成2路频率可控的时钟信号作为LTC1064的时钟输入,分别调节高通和低通滤波器的截止频率,从而实现带通滤波器的中心频率可调节,最后针对开关电容滤波器的直流偏移和时钟馈通问题进行后置滤波电路的设计.spice模型仿真结果表明,此带通滤波器的各项指标均达到了设计要求.     

一款平顶特性窄带滤波器的设计

为满足地球物理勘探中频域测试的需求,利用数值计算的方法,计算并得出了两级级联的有源带通滤波器在临界偏调时各级中心频率f0与Q值的关系;据此设计并制作了具有平顶特性的窄带通滤波器.实测结果表明其特性与理论计算曲线一致.此外,还对电路的选择性、灵敏度、平顶宽度以及等效噪声带宽等参数作了进一步讨论.建议利用该电路设计成50Hz工频陷波器.     

一种新型微带开环滤波器的设计

对于现代移动通信设备对微波滤波器的小型化、高带外抑制的要求,提出1种基于开环谐振子的微带带通滤波器.通过一定数目的开环谐振子,产生1对传输极点,提高滤波器的带外抑制,讨论了这种滤波器的设计流程,包含了相应的公式以及精确的计算.实际设计了1个八阶开环滤波器,中心频率为1 123 MHz,相对带宽为9.534%,带外50 ...     

IIR数字滤波器设计

介绍了利用双线性变换法设计巴特沃斯无限长单位冲激响应(IIR)数字滤波器.具体设计步骤如下:按一定的技术指标将给出的数字滤波器转换为模拟低通滤波器;根据转换后的技术指标设计模拟低通滤波器H(s);再将H(s)转换成H(z).对于高通、带通或带阻数字滤波器的设计,先将其技术指标转化为与之相应的作为"样本"的低通模拟滤波器的技术指标,再进行频率变换,然后按上述步骤设计出低通H(s),再将H(s)转换为所需的H(z).     

基于有源滤波器的电力系统间谐波抑制研究

目前电力系统中间谐波的污染日趋严重,必须对间谐波引起高度的重视.从实际应用的角度出发,阐述了有源滤波器有限长冲激响应滤波器和无限长冲激响应滤波器的原理,通过Matlab软件对等波纹线性相位FIR带通滤波器、加卡塞尔窗的FIR带通滤波器和巴特沃斯IIR型带通滤波器的滤波仿真,得出巴特沃斯ⅡR型带通滤波器对间谐波的抑制作用...     

中心频率可调节的低频带通滤波器设计与实现

在地磁弱信号检测处理过程中,接收端需要放大非常微弱频率很低的信号,因此要求放大器具有低噪声、高增益,滤波器应满足带宽窄中心频率可调节的功能.开关电容滤波器可实现低通、高通、带通和带阻滤波功能,而且中心频率可调节,本文采用了MF10开关电容滤波器集成模块进行电路设计,时钟频率由CD4046锁相环控制.实验结果表明本文设计的滤波器通带宽度达到20Hz,中心频率从1kHz到3kHz可调节,满足实际需要.     

同步调谐可变带通滤波器的设计

中心频率固定而带宽变化的可变带通滤波器广泛应用在许多电子测量仪器中,本文首先介绍了可变带通滤波器的实现背景,并着重介绍了可利用同步调谐滤波器来实现这种滤波器的理论依据和实际电路.通过电路分析和数学推导可以证明,电路中采用幅度补偿是可行的,并具有优势.     

供电与通信复用电路带通滤波器设计

供电与通信复用电路系统接入电网或者非线性负载时,噪声干扰不利于信息准确解调,为解决这一问题,设计一种应用于复用电路的带通滤波器.首先对巴特沃斯滤波器和切比雪夫滤波器性能进行比较,重点研究了巴特沃斯滤波器响应与级数之间的关系,最后提出了这种带通滤波器参数设计方法.通过实验验证了该带通滤波器在体现基波频率包络变化的同时可有效抑制噪声干扰,提高了通信解调电路的可靠性.     

LPC2138为控制核心的二阶程控滤波器设计

本文利用MAX266芯片设计了一种二阶程控滤波器。该滤波器以LPC2138为控制核心,由可编程运算放大器NE5532、模拟滤波器芯片MAX266和按键显示功能模块组成。通过键盘设置参数,实现放大器放大增益步进调节、滤波器带通频率步进调节功能。实验时,利用TDS2002Tektronix示波器显示程控滤波器的输出幅值,结果表明:滤波器带通频率的误差范围小于8.54%。     

可调SIR腔体带阻滤波器设计

提出了一种中心频率可调的阶跃阻抗谐振器(Step impedance resonator,SIR)腔体带阻滤波器,通过调谐螺杆的长度来灵活调谐中心谐振频率。仿真结果显示,该带阻滤波器中心频率调谐范围为1.5~2.05GHz。与传统的开路短截线带阻滤波器相比,实现了带阻滤波器中心频率的自由调谐,提高了带阻滤波器灵活性,并将寄生阻带精确推移到4倍阻带中心频率处,增加了上通带宽度。     

用第二代电流控制传输器（CCCⅡ±）实现二阶电流模式滤波器

提出了实现二阶电流模式滤波器的新电路,该电路使用第二代电流控制传输器(CCCII)和3个无源元件(1个电阻和2个电容),实现高输出阻抗二阶低通、带通电流滤波器.本电路具有结构简单、有源和无源元件灵敏度低等特点.经PSPICE仿真验证了设计的正确性.     

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。     

基于并联负载发夹型谐振器的四阶带通滤波器

针对现代无线通信系统中平坦带通滤波器的需求,提出了一种并联负载的发夹型谐振器,并利用提出的谐振器构建了四阶平坦带通滤波器。首先,通过在发夹型谐振器磁场最强的位置（中心位置）设置电阻,设计了一种新的并联型谐振器,从而可以通过改变电阻值来灵活地调整固有品质因数;其次,采用具有高、低固有品质因数的耦合拓扑来构建四阶平坦带通滤波器。最后,在印刷电路板上制备了一个具有传输零点和平坦带通的四阶带通滤波器。实验结果表明,该四阶带通滤波器的实测结果与仿真结果吻合较好,与其他多阶带通滤波器相比,该四阶带通滤波器具有可灵活控制的固有品质因数和小于0.2dB通带平坦度。     

电流模式八阶带通滤波器设计

本文提出了实现电流模式八阶带通滤波器的新方法,该法采用第二代改进式电流传送器构成的二阶电流模式带通滤波器作为基本积木块,得出了电流模式八阶带通滤波器的跳耦实现电路。该设计电路所有电阻,电容均接地,有利于电路集成化。     

Experimental studies on realization of fractional inductors and fractional‐order bandpass filters

This paper presents the hardware realization and performance study of fractional inductors of order 0 < α < 2. The fractional inductors used in this work have been realized with the help of general impedance converter circuit and fractional capacitors. Impedance characterization of fractional inductors with different exponents has been carried out experimentally. Also a generalized approach to design a fractional‐order bandpass filter is discussed in this work. The fractional‐order bandpass filter consists of a series combination of a resistor, a fractional inductor of order 1 < α < 2, and a fractional capacitor of order 0 < β < 1. The performance of fractional‐order bandpass filters has been studied and compared with corresponding integer‐order filters through both experimentation and simulation. Copyright © 2014 John Wiley & Sons, Ltd.     

Compact third-order microstrip bandpass filter designed by the distributed- to lumped-element equivalence

In reality, it is not easy to design microstrip filters for the sake of distributed-element effect. It is an effective approach to approximate distributed-element structures through appropriate lumped-element circuits. In this paper, some basic microstrip structures are discussed, whose equivalent lumped-element circuits are derived. Then, a novel microstrip filter is obtained by connecting these microstrip structures, according to the similar topology of the third-order lumped-element bandpass filter. The equivalent lumped-element counterpart of the proposed microstrip filter clearly reveals its physical mechanism, ie, how the resonances are created and coupled and how the transmission zeros are created. Furthermore, a set of the design formulas are presented, which can be used to calculate initial structure parameters and then facilitate design process. The proposed microstrip bandpass filter can realize a third-order elliptic bandpass response with one transmission zero at each side of the passband. In addition, two short-circuited stubs are added to input/output ports to create the third transmission zero. The filter is featured by good frequency selectivity and out-of-band suppression. For demonstration, an actual example was designed, fabricated, and measured.     

Electronically tunable low-component-count current-mode biquadratic filter using dual-output current followers

In this paper, a realization of a current-controlled three-input single-output current-mode universal biquadratic filter using dual-output current followers (DO-CFs) as active components is described. Based on the use of the current-controlled conveyor working as the DO-CF, the proposed circuit employs only two DO-CFs and two grounded capacitors that provide the advantage of an electronic tuning capability and is of special interest from the IC fabrication point of view. By suitably selecting three input signals, the filter can realize all of the standard biquadratic filtering functions, i.e., lowpass, bandpass, highpass, bandstop and allpass, all at a high impedance output which enables easy cascading in the current-mode operation. The natural angular frequency (ω _o ) and the bandwidth (BW) of the proposed circuit can be tuned independently and electronically over a wide range by adjusting the external bias currents. In addition, no critical component matching conditions are required for all the filter response realizations, and both active and passive sensitivities are low. PSPICE simulation results are used to confirm the characteristics of the proposed circuit.     

Current‐mode dual‐output ICCII‐based tunable universal biquadratic filter with low‐input and high‐output impedances

A new tunable current‐mode (CM) biquadratic filter with three inputs and three outputs using three dual‐output inverting second‐generation current conveyors, three grounded resistors and two grounded capacitors is proposed. The proposed circuit exhibits low‐input impedance and high‐output impedance which is important for easy cascading in the CM operations. It can realize lowpass, bandpass, highpass, bandreject and allpass biquadratic filtering responses from the same topology. The circuit permits orthogonal controllability of the quality factor Q and resonance angular frequency ω_o, and no component matching conditions or inverting‐type input current signals are imposed. All the passive and active sensitivities are low. Hspice simulation results are based on using TSMC 0.18 µm 1P6M process complementary metal oxide semiconductor technology and supply voltages ±0.9 V to verify the theoretical analysis. Copyright © 2012 John Wiley & Sons, Ltd.     

一种LCCL滤波器及其在半桥电力有源滤波器中的应用

提出一种新型高阶电力滤波器,将其命名为LCCL滤波器。与传统的LCL滤波器相比,LCCL滤波器通过在网侧电感支路并联一个小电容,使网侧电感与并联电容在开关频率处发生并联谐振。谐振使LCCL滤波器网侧支路在开关频率处呈现无穷大的阻抗,相比LCL滤波器可以更好地抑制开关频率附近电网电流纹波,减小电网电流THD。与LLCL滤波器相比,LCCL滤波器具有较好的抑制参数变化的能力,在考虑电网内阻抗时,拥有更好的高频纹波抑制性能。同时,可以更容易地进行基于电容电流反馈有源阻尼的控制器设计。LCCL滤波器作为电压源型逆变器(VSI)与电网的接口,可应用于PWM整流器、有源电力滤波器(APF)和通用电能质量控制器(UPQC)等多种场合。通过以半桥APF为例,讨论了LCCL滤波器的参数选择方法和控制器设计。最后,通过仿真和实验验证了LCCL滤波器的可行性。     

高压直流输电交流滤波器参数的计算

无功补偿和电压控制是高压直流输电工程中的重要问题。交流滤波器可以滤除交流侧谐波并补偿无功功率,所以广泛应用于高压直流输电工程中。交流滤波器必须满足在各种工况下的交流侧谐波性能和无功功率补偿要求。首先给出单调谐滤波器参数计算的方法和精确公式;在双调谐和三调谐滤波器的参数计算过程中,通过把双调谐、三调谐滤波器等效成2个或3个单调谐滤波器,先计算得到各个单调谐滤波器参数,再经过该文给出的等效公式得到双调谐和三调谐滤波器参数,并通过定值计算和性能计算验证交流滤波器的元件参数能够符合系统要求。给出了一个三调谐滤波器计算的例子。通过仿真,得到三调谐滤波器和等效的3个单调谐滤波器的阻抗频率特性曲线,并加以对比,结果表明这种参数计算方法符合工程精度要求。介绍了另一种基于交流滤波器阻抗频率特性的滤波器参数计算方法并将两者做了对比,分析了2种滤波器参数计算方法的优缺点。