一种带宽自适应的滤波器

设计了一种全新的带宽自适应滤波器。主要特点是:在输入信号频率不确定或时变的情况下,能够通过对输入信号频率的探测而自适应的调节滤波器带宽。该结构被成功地应用在了模拟处理器内,有效地实现了对频率不确定或时变的输入信号进行低通或带通滤波处理。滤波器由四阶的全差分开关电容电路实现,带宽可在直流到40kHz内自适应调节。整个电路基于0.18μmCMOS工艺实现,电源电压3.3V,功耗为560μW。芯片测试结果表明,电路具有良好的自适应滤波性能。     

自适应CCCII-OTA型多功能滤波器设计

研究相关高性能滤波的理论知识,利用电流模式电路信号处理速度快、频带宽的优势,来设计由CCCII(电流控制电流传输器)与OTA(跨导运算放大器)构成的滤波器,其中MCCCII为CCCII的多输入多输出型。设计了(F/I)频率电流转换电路,解决了现有F/I电路频率电流转换信号频率低、速度慢的问题,最后设计了(V/I)电压转电流电路;以上各部分电路有效级联实现了自适应CCCII-OTA滤波器。文章完成了具有滤波频率自适应功能的CCCII-OTA型滤波器,它实现了输入信号频率改变通频带的动态功能。它可以应用在频率测量、频率特性分析、谐波分析等信号检测领域,具有重要理论意义。     

UHF RFID阅读器中可编程全差分低通滤波器的设计

基于TSMC 0.25 μm RF CMOS工艺,提出了一种应用于860～960 MHz UHF波段单片射频识别(RFID)阅读器的可编程全差分低通滤波器电路.该滤波器为6阶切比雪夫有源RC滤波器,其中的运放采用带共模反馈的全平衡差动放大器结构(FBDDA)实现了全差分的缓冲器.仿真结果表明:该电路可以通过3位信号控制位产生截止频率为400 kHz、600 kHz、800 kHz、1 MHz以及1.3 MHz的全差分低通滤波器,1 MHz处的点噪声为20 nV/Hz,1 dB输入压缩点为15 dBm,3.3 V电源电压下电路消耗总电流为4.86 mA.     

一种基于开关电容的可配置多模滤波器

设计了一种基于开关电容的可配置多模滤波器,由模拟信号处理模块、数字控制模块和参考电压电流源组成;通过数字控制模块配置滤波器工作在旁路、低通、带通、自适应工作状态,同时实现低通滤波器截止频率和带通滤波器中心频率可调;自适应滤波器截止频率和中心频率能准确跟随输入信号主频率.整个电路基于SMIC 0.18μm CMOS工艺实...     

全差分可调频率四阶Chebyshev滤波器的实现

提出了一种新的全差分运算放大器,该运算放大器在具有电压共模负反馈的同时还具有电流共模负反馈,能较好地稳定其工作点。通过利用MOS管工作在线性区便能作可变电阻之用的特性,设计实现了基于R-MOSFET-C运放的全差分频率连续调节的四阶Chebyshev低通滤波器。该滤波器采用台湾联电(UMC)2层多晶硅、2层金属(2P2M)5V电源电压、0.5m CMOS工艺生产制造。其芯片面积大小为0.36mm~2,截止频率调节范围为20kHz到420kHz,输入信号频率在100kHz,2.5Vpp时的失真小于-65dB,功耗仅为16mW。     

一种用于水听器电压检测的模拟前端电路

提出了一种用于水听器电压检测的模拟前端电路,包括低噪声低失调斩波运算放大器,跨导电容(gm-C)低通滤波器,增益放大器三部分主体电路;低噪声低失调斩波运算放大器用于提取水听器前端传感器输出的微弱电压信号;gm-C低通滤波器用于滤除电压信号频率外的高频噪声和高次谐波;最后经过增益放大器放大至后级模数转换器的输入电压范围,输出数字码流;芯片采用台积电(TSMC)0.18μm单层多晶硅六层金属(1P6M)CMOS工艺实现。测试结果表明,在电源电压1.8 V,输入信号25 kHz和200 kHz时钟频率下,斩波运放输入等效失调电压小于110μV;整体电路输出信号动态范围达到80 dB,功耗5.1 mW,满足水听器的检测要求。     

全差分群时延可精确调节的四阶Bessel滤波器实现

采用全差分运算放大器、无源电阻以及用作可变电阻的MOS管设计实现了全差分R-MOSFET-C四阶Bessel有源低通滤波器,在所提出的电路中通过调节工作在线性区的MOS管有源电阻的阻值以抵消集成电路制造工艺过程中电阻阻值的一致性偏差,达到Bessel滤波器的群时延值得到精确设计的目的.该滤波器中所采用的全差分运算放大器不仅具备有电压共模负反馈,而且还具有电流共模负反馈,极有利于电路静态工作点的稳定.通过无源双端RLC原型低通滤波器导出的0.75μs群时延四阶Bessel滤波器,采用台湾联电(UMC)2层多晶硅、2层金属(2P2M)、5.0V电源电压、0.5μm CMOS工艺制造,在输入信号为100kHz、2.5Vpp时,其谐波失真(THD)值低于-65dB.     

一种基于FDDA的全差分Sallen-key低通滤波器

在传统Sallen-key低通滤波器的基础上,利用一个全差动差分放大器(FDDA),设计了一种新型的全差分Sallen-key低通滤波器。该滤波器能有效抑制共模噪声,大幅减少功耗。电路参数取决于电容之比和电阻之比,具有较高的精度。截止频率和品质因数独立可调,易于分析和设计。电路结构简单,通带增益范围广,无源灵敏度较低。相比传统的两个单端Sallen-key滤波器,该滤波器降低功耗达50%以上。采用0.18 μm CMOS工艺进行设计,电源电压为3.3 V。仿真结果表明,功耗仅为532 μW。在1 kHz频率下,输入参考噪声为542.9 nV·Hz-1/2。     

一种新型的跟踪低通滤波器

介绍了一种新型的跟踪低通滤波器的原理及实现方法.该跟踪低通滤波器用八阶椭圆型开关电容滤波器MAX293构成低通滤波电路,输入信号的频率通过单片机的测量、修正、倍频处理后输出作为MAX293的时钟控制频率,用以控制MAX293的截止频率从而实现跟踪滤波.实验证明,对于0.1 Hz～25 kHz的信号,跟踪低通滤波器的截止频率相对误差小于1%.     

低频段自适应梳状滤波器的研制

滤波器电路是信号处理系统中的重要器件，自适应梳状滤波器是滤波器本身根据输入信号选择滤波器通路的一种电路，它大大减小了滤波器的带通宽度，降低了器件噪声，提高了信号接收器的精度。该文中设计的自适应梳状滤波器是由六波段滤波器组成，接收信号的频率为3kHz～120kHz，降噪范围是单一滤波器的1／6～1／5。     

DDC中的抽取滤波器设计及FPGA实现

本文介绍了在数字下变频（DDC）中的抽取滤波器系统设计方法和具体实现方案。采用CIC滤波器、HB滤波器、FIR滤波器三级级联的方式来降低采样率。通过实际验证，证明了设计的可行性。     

波导带通滤波器的精确设计和快速优化

介绍了采用三维微波电磁场仿真软件快速提取直接耦合波导带通滤波器耦合窗口参数的方法,并提出了优化最终模型的快速扫描技术.全波仿真及实验结果表明,该方法能满足波导带通滤波器快速精确设计的要求.     

Inverse Ultraspherical Filters

The inverse ultraspherical filter is derived and its properties analyzed. It is shown that the inverse ultraspherical filter has smaller transition band than the inverse Chebyshev filter under certain circumstances while still maintaining the maximally flat passband characteristic. Filter pole and zero calculations are described and typical magnitude and delay responses generated. Nomographs of inverse ultraspherical filters are also provided for determining filter order and for possible magnitude response optimization.Celestino A. Corral was born in Havana, Cuba. He earned his Bachelors, Masters and Ph.D. degrees in electrical engineering from the University of Miami, Florida, in 1985, 1987, and 1993, respectively. He completed his Ph.D. program under a Patricia Roberts Harris fellowship. From 1988 to 1990 Dr. Corral was a Member of the Technical Staff at Sandia National Laboratories, Albuquerque, New Mexico, where he was involved in the analysis, modeling, and design of custom circuits for piezoelectric sensor components. In 1994, he joined Scientific-Atlanta in Atlanta, Georgia, as an Associate Staff RF Engineer and worked on communication systems and specialized microwave software. In 1997 he was Senior Design Engineer at Origin Data Systems in Boca Raton, Florida, where he had multiple roles in system, hardware, and software development for a novel asset management/RFID system. Currently, Dr. Corral is a Distinguished Member of the Technical Staff in Motorola Labs, Plantation, Florida, and is involved in ultra-wideband, wideband, and propagation research. His interests include circuit and filter theory, communication systems, numerical analysis, signal processing, and constrained optimization. He has published over twenty-five journal and conference papers, has six patents filed, and two trade secrets.Dr. Corral was principal recipient of the Myril B. Reed Best Paper Award for the 40th Midwest Symposium on Circuits and Systems in 1997. Dr. Corral is also the principal recipient of the Ambrose Fleming Premium for IEE Proceedings on Circuits, Devices, and Systems, 2000. Dr. Corral is a Senior Member of IEEE and a member of Omicron Delta Kappa, Tau Beta Pi, and Eta Kappa Nu honor societies.     

Design of two-dimensional directional filters

A directional filter has a passband extending fully along a straight line passing through the origin. In its original form the transformation technique, a powerful tool for designing two-dimensional FIR filters, is not useful to design such a filter. In this communication we suggest a few analytical and optimisation-based methods to design directional filters using the transformation technique. The superiority of the proposed methods over existing techniques is demonstrated.     

一种基于CIC滤波器的有效锐化方法研究

介绍了对积分梳状滤波器（CIC滤波器）的有效锐化。所提出的锐化滤波器的结构由两个主要部分组成：一个梳状滤波器的级联部分和一个锐化滤波器部分。所提出的方案使得滤波器中锐化部分的工作速率比输入速率大为降低，其频谱响应特性比传统的也有所改进。通过MATLAB仿真，可看出改进锐化后的滤波器性能更优。     

Current-mode continuous-time filters using complementary current mirror pairs

A design of current-mode continuous-time filters for low voltage and high frequency applications using complementary bipolar current mirror pairs is presented. The proposed current-mode filters consist of simple bipolar current mirrors and capacitors and are quite suitable for monolithic integration. Since the filters are based on the integrator type of realization, the proposed method can be used for a wide range of applications. The frequency of the filters can easily be changed by the DC controlling current. A fifth-order Butterworth and a third-order leapfrog filter with tunable cutoff frequencies from 20 MHz to 100 MHz are designed as examples and simulated by SPICE using standard bipolar parameters.     

Miniaturized dielectric waveguide filters

Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.     

大功率谐波吸收式滤波器设计

介绍了大功率谐波吸收式滤波器的实现电路，这些电路满足了信号分流的技术要求。文中给出了详细的工作原理和测试数据。     

一种数字下变频抽取滤波器的设计

对一个针对数字下变频应用的抽取滤波器从设计指标到版图实现的设计过程进行了详细介绍.该抽取滤波器实现了20倍的降采样,由CIC滤波器、CIC补偿滤波器和半带滤波器三级依次串联而成.通过利用抽取滤波器的等价变换和多项分解性质,各滤波器级的硬件电路开销和运行功耗都得到了降低.     

Single-stage line-coupled ac/dc converter with high power factor and ripple-free input current

Single-stage line-coupled ac/dc converter with high power factor and ripple-free input current is proposed. The proposed power factor correction circuit can achieve high power factor and ripple-free input current using a coupled inductor. Experimental results for a 400?W converter at a constant switching frequency of 100?kHz are obtained to show the performance of the proposed converter.