基于对数域无损积分器的高阶滤波器设计

提出利用双极型晶体管构成的对数域无损积分器以及对数压缩和指数扩展电路实现高阶滤波器.基于无源网络模拟,该设计不仅方法简单,而且使用元件种类很少,易于集成给出一个6阶Butterworth带通滤波器设计实例.PSpice仿真结果表明,该对数域滤波器能在低电压条件下工作,并具有高频、宽调谐范围和低失真等特性.     

基于单自由度振动模型的IIR数字滤波器设计

无限冲击响应(IIR)数字滤波器设计通常需要先设计S域滤波器,再变换到Z域。为简化IIR数字滤波器的设计过程,本文提出利用单自由度系统(SDOF)模型直接设计IIR数字滤波器的方法,包括低通、带通、高通、带阻等。仿真结果表明设计过程直接、简单,滤波器参数不需要随采样频率而变,具有良好特性,是一种设计IIR数字滤波器的简便易用的新方法。     

用双线性变换法设计IIR滤波器

给出了用双线性变换法设计IIR数字滤波器的方法,并通过用MATLAB语言来实现。双线性法可以使系统经变换后仍保持原有特性,而且这种方法是S域和Z域的单值一一对应,克服了频率交叠产生的混叠效应;最后使用MATLAB语言实现了满足要求的低通IIR滤波器,从而证明了椭圆滤波器具有最优特性。     

对数域积分电路的分析与应用

本文分析了一种对数域积分电路的特性,以及极间电容对其性能的影响.在此基础上给出了一般对数域滤波器的设计方法,以及其在宽频带的流控振荡器(ICO)和锁相环电路中的应用,并给出了模拟结果.     

用对数域电流模式电路实现连续小波变换

本文提出了用对数域电路实现连续小波变换的一种方法.利用复解调技术将设计带通滤波器组转化为设计相对简单的低通滤波器组问题,给出了分解与重构的系统流程.设计并分析了对数域电流控制振荡电路,对数域积分器和高斯滤波器等主要的模拟电路.     

光格型FIR奇偶交错滤波器设计

用光格型有限冲激响应(FIR)滤波器模型在z变换域对耦合器级联形式的奇偶交错滤波器进行了理论分析,根据由目标滤波函数求解光格型阵列具体参数(单位时延△τ和耦合角θk)的算法编写了相应的计算程序,讨论了通带和阻带边界归一化频率位于0.5附近的z域低通滤波器和光域奇偶交错滤波器的对应关系.在此基础上设计了a～e五种滤波器,其幅频响应特性曲线类似矩形,通带顶部平坦、纹波接近于0 dB,隔离度可以达到50 dB.     

基于信号流图的任意阶对数域滤波器设计

本文给出了一种基于信号流图的任意阶对数域电流模式滤波器的通用设计方法.用该方法产生的,n阶滤波器由2n个对数单元电路和n个接地电容组成,易于集成.在此基础上给出了三阶Butterworth滤波器的设计实例及其PSpice计算机模拟结果.     

EMI滤波器的精确设计

本文介绍了一种精确设计EMI滤波器的方法.为了得到合适的滤波器插入损耗,滤波器设计中不但要考虑电路的干扰特性还要考虑电路的输入阻抗特性.     

波数字滤波器传输特性的计算机辅助分析

正 1.引言 波数字滤波器(以下简写为WDF)因具有低灵敏度性质,可用较短的系数字长加以实现而得到重视。一般的数字滤波器的设计往往是先寻求其传输特性表达式,然后考虑实现的结构。WDF则不然,它直接引用模拟滤波器的结构,将模拟元件及其联接方式变换到数字域即形成WDF的数字结构,而其在数字域上的传输特性则常是待求的。关于     

椭圆函数滤波器边带特性优化方法

本文对椭圆函数滤波器边带特性优化方法进行了研究,给出了一种新方法的详细分析、算法和设计实例.该方法充分利用滤波器阶数余量,通过相应的计算方法在不增加阶数的前提下使滤波器边带选择特性最大化,有效地减小了过渡带宽.     

Low-Voltage Log-Domain Complex Filters

Two systematic methods for designing low-voltage log-domain complex filters are introduced in this paper. The first one is based on the transposition of the signal flow graph representation of the linear-domain complex leapfrog prototype filter to the corresponding one in the log-domain. The last one is based on the transposition of the wave equivalents of the elements of the complex passive prototype filter to the corresponding log-domain complex equivalents. Both transpositions are performed by employing an appropriate set of complementary operators that facilitates the derivation of low-voltage log-domain filter configurations. Two design examples are given, where a 12th-order log-domain complex transfer function is realized in order to fulfill the Bluetooth specifications. The derived log-domain filter structures operate at a single 1.2-V-power supply-voltage, and their behavior was evaluated through simulation results. In addition, a comparison concerning important quality factors of both of the proposed structures is performed, and the obtained results are further discussed.      

A novel first-order log-domain allpass filter

This paper proposes a first-order allpass log-domain filter, which is systematically derived using the state-space synthesis procedure. To the best knowledge of the authors, the filter is the first log-domain first-order allpass filter in the literature. The proposed filter has a simple structure and can be electronically tuned. PSPICE simulations are given to confirm the theoretical analysis.     

Log-domain wave filters

A systematic method for designing log-domain wave filters is presented. Wave filters simulate topologically and functionally passive doubly terminated LC ladder prototype filters of low sensitivity. The design in the log-domain is based on a transposition of the signal flow graph (SFG) that corresponds to the wave equivalent of elementary two-port blocks in the linear domain, to the corresponding log-domain SFG. This is achieved by using an appropriate set of complementary operators, in order to preserve the linear operation of the whole circuit. Simulation results of a fifth-order low-pass and a fourth-order bandpass log-domain wave filter are given, using HSPICE. The proposed circuits are suitable for low-voltage operation and in high-frequency applications.     

低电压全BJT高阶对数滤波器设计

提出了一种1.2 V低电源电压全BJT任意阶低通对数滤波器的设计方法.该方法是由传输函数直接设计低通对数域滤波器,得到最优的BJT跨导线性单元和滤波器系统状态空间后,利用最优状态空间描述滤波器系统,对微分方程中的每一项,使用最优BJT跨导线性单元设计其对应的电路,进行组合,从而得到低通对数滤波器,实现了不同阶数、不同纹波的切比雪夫低通滤波器,理论分析和Pspice实例仿真表明,该方法能最优地实现所需电路的设计,具有电路简洁和低电压的特点.     

Low-power Analog VLSI Implementation of Wavelet Transform

For applications requiring low-power, low-voltage and real-time, a novel analog VLSI implementation of continuous Marr wavelet transform based on CMOS log-domain integrator is proposed.Mart wavelet is approximated by a parameterized class of function and with Levenbery-Marquardt nonlinear least square method,the optimum parameters of this function are obtained.The circuits of implementating Mart wavelet transform are composed of analog filter whose impulse response is the required wavelet.The filter design is based on IFLF structure with CMOS log-domain integrators as the main building blocks.SPICE simulations indicate an excellent approximations of ideal wavelet.     

Log-domain filtering by simulating the topology of passive prototypes

A systematic method for designing log-domain filter structures that simulate the topology of the corresponding passive prototypes is introduced in this paper. This has been achieved by transposing the i-/spl upsi/ characteristic equation of each passive element in the linear domain, to the corresponding one in the log domain. The transposition has been done in such a way that, the current that flows through the terminals of the passive element in the linear domain sustains its value in the corresponding log-domain configuration. In this way the linear operation of the whole filter is preserved. With regard to the voltage at each terminal of the passive prototype, this is logarithmically compressed in order to achieve filtering in the log domain. Following the above considerations, the log-domain equivalents of all passive elements of the prototype filter were derived. Having established the equivalents, the procedure for designing high-order log-domain filters is quite facilitated. The validity of the proposed technique is demonstrated through simulation results for a fifth-order elliptic low-pass filter.     

基于CMOS对数域积分器的小波变换模拟VLSI实现

提出了一种基于CMOS对数域积分器的连续Marr小波变换模拟VLSI实现方法.构造了Marr母小波时域逼近函数模型,用Levenbery-Marquardt非线性最小二乘法求解模型参数最优解,得到母小波逼近函数.设计了以CMOS对数域积分器为积木块的小波变换电路,该电路由冲激响应为母小波逼近函数及其伸缩函数的滤波器组构成,滤波器组采用低灵敏度的IFLF结构进行综合.SPICE仿真结果表明该方法的可行性.