Realization of multiple-output biquadratic filters using current differencing buffered amplifiers

In this paper, multiple-output multifunctional biquadratic filters using current differencing buffered amplifiers (CDBAs) as active elements are presented. The proposed circuit configuration is mainly composed of the CDBA-based cross-coupled feedback configuration and the simple CDBA-based voltage substractor. By an appropriate choice of virtually grounded passive components, the configuration can simultaneously realize lowpass, highpass, bandpass, bandstop and allpass voltage transfer functions, all at low resistance outputs. The natural angular frequency and the quality factor can orthogonally controllable. Experimental results verifying the theoretical analysis are also given.     

A versatile signal flow graph realization of a general current transfer function

A general synthesis procedure is given for a versatile signal flow graph realization of a general current transfer function by using multi-output second generation current controlled current conveyors (MO-CCCIIs). The proposed configuration uses $n+1$ multi-output second generation current conveyors (MO-CCIIs), n capacitors and at most $2(n+1)$ resistors. This number of resistors can be reduced to n for special cases. Using MO-CCCIIs instead of MO-CCIIs, the resistors can be removed completely for the nth-order universal structure. The general transfer function having any numerator dynamics can be derived from the universal structure by using a single MO-CCCII and at most $n+1$ resistors. It is very easy to find the values of the passive elements from the coefficients of the transfer function to be realized. The validity of the proposed synthesis is verified through PSpice simulations.     

电流模式N阶CDBA-RC通用滤波器的系统设计

该文提出了利用电流差分缓冲放大器CDBA(the Current Differencing Buffered Amplifier)实现n阶电流模式滤波器的方法。基于信号流图给出了系统的设计公式,并举例设计了5阶Butterworth低通、高通及4阶Butterworth带通滤波器。PSPICE仿真表明,结果与理论分析完全吻合。该滤波器不仅电路结构简单,而且用的元件数目很少。     

电压型双二次滤波函数的CFA实现

提出了一种采用电流反馈放大器（current-feedback amplifier,CFA)实现的电压模式双二次滤波函数断电器，同时得到了陷波、高通、带通、低通和双二次滤波函数输出。且极点角频率与品质因素独立可调。计算机仿真结果与理论分析相符。     

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.     

RECONSTRUCTION OF ONE DIMENSIONAL MULTI-LAYERED MEDIA BY USING A TIME DOMAIN SIGNAL FLOW GRAPH TECHNIQUE

A novel inverse scattering method to reconstruct the permittivity profile of one-dimensional multi-layered media is proposed in this paper.Based on the equivalent network ofthe medium,a concept of time domain signal flow graph and its basic principles are introduced,from which the reflection coefficient of the medium in time domain can be shown to be a series ofDirac δ-functions(pulse responses).In terms of the pulse responses,we will reconstruct both thepermittivity and the thickness of each layer will accurately be reconstructed.Numerical examplesverify the applicability of this method     

一种新型通用有源电流模式滤波器的设计

本文在建立了MOS场效应管小信号模型的基础上，采用信号流图的方法设计了一个三输入-输出的二阶通用有源电流模式滤波器。该滤波器能够通过合理的选择输入电流实现不同的滤波功能，并可通过改变滤波器电路的工作条件来实现不同参数的滤波。并推导出这种结构的滤波器具有低灵敏度的特性，最后、进一步总结了这种结构的滤波器的优缺点。