用SFG法设计OTA—C滤波器

本文提出了由传递函数的信号流图直接设计ＯＴＡ－Ｃ滤波器的方法。成功的设计了未见发表的３种一阶电路和３种二阶电路，为ＯＴＡ－Ｃ滤波器的设计提供了一简捷，直观的方法。     

低阶阻抗的OTA—C模拟电路实现

提出一种接地和浮地你阶阻抗元件的ＯＴＡ－Ｃ模拟电路设计方法,给出了电路在滤波器设计中的应用示例。     

n阶电压转移函数的OTA实现

文中提出了一种ｎ阶任意类滤波器的设计方法。基于信号流图并采用ＣＭＯＳＯＴＡＱ实现，得到了ｎ阶ＯＴＡ滤波器电路。     

CMOS跨导电容滤波器

提出了采用ＭＯＳＭＯＯＴＡ、ＭＩＯＴＡ和电容器设计任意滤波器的方法。通过网络函数的直接模拟，导出了任意主阶传输函数的两种ＯＴＡ－Ｃ实现电路，并在此基础同了具有最不秀源元件的任意波器。文中给出了滤波器的设计实例和ＰＳＰＩＣＥ模拟分析，以证明本文所提方法的可行性。     

采用单运算跨导放大器的混合模式滤波器

提出了一种新颖的单运算跨导放大器的混合模式滤波器电路。由该电路可实现一阶低通,一阶高通,二阶低通及二阶带通滤波器,所有滤波器仅由一个ＯＴＡ及３－４个ＲＣ元件构成。分析了各种滤波器的灵敏度,并给出了实验结果。     

通用高阶OTA—C滤波器的信号流图实现

以传递函数的信号流图实现为基础，设计了一种新的通用阶可调ＯＴＡ－Ｃ滤波器，这种滤波器只需要ＯＴＡ器件和接地电容，适合于ＭＯＳ技术集成，计算机模拟结果表明了它的可行性。     

一种新的通用高阶OTA—C滤波器的设计

本文提出以传递函数的信号流图实现为基础，设计出一种新的通用高阶可调ＯＴＡ－Ｃ滤波器。该滤波器仅需要ＯＴＡ器件和接地电容，适合于用ＭＯＳ技术实现。实验结果证明了它的可行性。     

一种将OTA-C电路转换为CFA-RC电路的方法--替换法

本文介绍了一种直接将基于跨导－Ｃ的电路（ＯＴＡ－Ｃ电路）转换成基于电流反馈放大器ＣＦＡ的电路（ＣＦＡ－ＲＣ电路）的方法－替换法,给出了ＣＦＡ－ＲＣ电路的设计表格。设计实例和实验结果证明了这种转换方法的正确性。     

基于单OTA的电压模式滤波器

提出了一个基于单ＯＴＡ的电压模式滤波器模型电路,该模型电路仅由一个ＯＴＡ 及三个ＲＣ元件构成。由该电路可产生出一阶低通、一阶高通及二阶低通、二阶带通滤波器。各滤波器具有很低的灵敏度。与诸文献［１～５］的ＯＴＡ滤波器相比,结构简单且三个ＲＣ元件中有两个接地,仅一个浮端,便于集成。文中还分析了各滤波器的截止频率和通频带,给出了电路的实验结果。     

信号流图OTA—C高通滤波器

本文提出了采用ＯＴＡ微分器设计高通滤波器的方法。基于有源滤波器的跳耦综合，导出了全极占炕通梯形滤波器的ＯＴＡ－Ｃ实现。该滤波器具有低灵敏度和高截止频率，与ＭＯＳ工艺兼容，便于单片集成，调整方便，文中给出了实验结果和Ｐ－ＳＰＩＣＥ模拟，证明此此滤波器的可行性。     

Trade-offs in the OTA-based analog filter design

Operational transconductance amplifiers (OTAs) are widely used in the design of electronically tunable circuits. However, electronic tunability ranges of the OTA based filters are restricted by the limited bandwidth of the transconductance gain of the OTA. Furthermore, stability conditions and the linearity of the OTA which depends on the control current restrict the tunability. In this paper, some trade-offs in the electronically tunable filters are investigated. In addition, the tunability ranges of some first and second order OTA-C and OTA-RC filters are comparatively examined. Moreover, an OTA-C all-pass filter circuit is presented. SPICE simulations are performed and stability analyses are given for both of the OTA-C and OTA-RC filters. Operation of the presented all-pass filter is verified experimentally.     

OTA正弦振荡器的系统产生方法

本文以双二次传递函数电压放大器为基本模块，采用信号流图(SFG)方法。设计了四大类OTA-C正弦振荡器。第一类除包括当今流行的四种电路外．其余的电路和另三类是迄今尚未见诸发表的新电路。     

全集成连续时间跨导电容滤波器的进展

过去１０多年来，全集成连续时间跨导电容（ＯＴＡ－Ｃ）滤波器已成为一类重要的滤波器电路。本文回顾了它的发展历史，综述了这一领域内的进展，指出了有待研究的有关课题。     

OTA-C filter design using inductor substitution and Bruton transformation methods

Operational transconductance amplifier-capacitor (OTA-C) filters are normally designed by simulating low sensitivity LC filters. The evaluation of parasitic effects on OTA-C filters for the inductor substitution method is usually by direct circuit analysis, which is too complex for high order filters. The practical performance of the Bruton transformation method in OTA-C filter design has not previously been investigated. The author presents a method for evaluating the parasitic effect in OTA-C filters based on the inductor substitution method, which uses very simple formulas for the magnitude and phase sensitivities of the passive LC ladder and the equivalent loss resistance and the change in the equivalent inductance of each OTA-C inductor due to nonidealities in its constituent OTAs. The Bruton transformation method is discussed and demonstrated not to be attractive for OTA-C filter design due to the large component numbers and parasitic effects     

电流模式高阶OTA-C高通滤波器的设计

提出了一种新的电流模式高阶OTA—C高通滤波器的设计方法。由该方法导出的滤波器具有最少的元件．n阶滤波器仅需n个OTAs和n个电容，所有的电容均接地，便于集成且与VLSI工艺兼容。文中给出了6阶滤波器设计实例，PSPICE仿真结果与理论分析相吻合，验证了该设计方法的可行性。     

OTA-C realisation of general high-order transfer functions

OTA-C technology has become a very important topic in continuous-time integrated circuits owing to its advantages over other realisation techniques. In the research of OTA-C filters, the synthesis of second-order filters has been widely investigated but the realisation of high-order transfer functions has not received similar attention. The authors propose a novel higher-order OTA-ground capacitor network and explicitly formulate realisation techniques for general transfer functions.<>     

Frequency-dependent harmonic-distortion analysis of a linearized cross-coupled CMOS OTA and its application to OTA-C filters

Recent progress of wide-band communication systems demands high-frequency circuits. Conventionally, the linearity of the operational transconductance amplifier and capacitor (OTA-C) has been analyzed using Taylor series expansion. Unfortunately, this approach does not predict the frequency-dependent linearity degradation. Thus, to properly design linearized OTAs, the frequency dependence of these coefficients must be determined. In this paper, we present a frequency-dependent harmonic-distortion analytical method applied to a linear-enhanced OTA. This OTA, which is suitable for high-frequency operation, uses three linearization techniques simultaneously: 1) attenuation through floating-gate MOS transistors; 2) source degeneration; and 3) polynomial cancellation techniques. By using the harmonic-distortion analysis, some properties on the performance of OTA are used to improve the performance of OTA-C based circuits at high frequencies. A 0.5-/spl mu/m CMOS OTA simulation and experimental results are shown to verify the harmonic-distortion analytical method.     

一种新的高阶全极点运算跨导放大器-C滤波器系统生成方法

提出一种高阶全极点运算跨导放大器-C滤波器系统生成方法，能方便地设计出全极点高通、低通和带通滤波器。该滤波器与MOS工艺兼容，便于单片集成。滤波器设计实例和PSPICE模拟结果表明所提方法是正确的。     

差分式连续时间CMOS OTA-C双二阶滤波器

应用信号流图法，提出了一种新颖的差分式连续时间电压模式CMOS跨导-电害双二阶滤波器，系统地生成了各种差分式电压模式二阶滤波器；讨论了滤波器的极点特征参数与灵敏度；面向实际电路完成了MOS管级的计算机仿真．仿真结果表明所提出的电路方案正确有效．适于全集成。     

一种新颖的高阶全极点OTA—C低通滤波器设计方法

本文提出一种高阶全极点OTA-C低通滤波器设计方法.用该方法对二～七阶Butterworth最平坦型低通滤波器进行了设计和SPICE模拟分析。同时证明了所提方法具有理论上严谨、工程上实用的特点。