有关放大线路的分析方法

放大线路是非线性电路。因为构成其电路的电子元件是非线性元件。要用他对信号进行不失真地放大 ,必须设置适当的工作点 ,使电子器件工作在近似线性区域 ,这就决定了放大器的分析包括直流分析和交流分析。而非线性器件对直流信号和交流信号所呈现的性能不同 ,这就是放大器分析与一般线性电路分析的不同之处 ,当对放大器进行小信号分析时 ,其电路模型又是线性的。但电子器件的非线性对于放大器的分析却一直起着重要的作用     

红外焦平面阵列读出电路非线性的研究

在红外焦平面阵列读出电路中,非均匀性是限制其发展的主要瓶颈之一.优化读出电路的非线性可以改善焦平面阵列的非均匀性,提高红外系统的成像质量.文章主要对电容跨阻抗放大器(CTIA)型读出电路的非线性进行研究,包括该结构的积分放大器、复位管以及采样保持电路的非线性,并在理论分析的基础上提出了优化单元电路非线性的方法,设计了一个高线性的CTIA型单元电路.具体电路采用0.5μm DPTM CMOS工艺设计,仿真结果表明该单元电路功耗低,动态范围大,线性度高达99.87%.     

高效率I类单电源音频功率放大器

设计了一种高效率单电源I类线性音频功率放大器。采用动态电源电压降低了功率管的压降,从而提高了放大器的效率。峰值输出功率时的最高效率超过80%。采用增益压缩技术使得该电路能够在单电源下工作。避免了使用电荷泵产生负电压,从而降低了电路的复杂度和芯片的面积。采用共模电压共享和对称版图布局降低了电路的非线性。在电源电压转换前后测得的THD N分别是0.01%和0.05%。向8欧姆负载提供的最大输出功率为410mW。与开关型的放大器相比,I类放大器是线性放大器因此具有比较低的EMI。高效率和低EMI的优点使得I类放大器适用于对射频干扰敏感的便携式设备。     

含运算放大器电路的图解分析

运算放大器在工作时具有两种状态:线性状态和非线性状态,分别对应其输入—输出特性的线性区和正、负饱和区。本文采用图解分析法讨论了含运算放大器电路的解及其解的特性,指出含运算放大器电路如采用负反馈接法,则其解唯一且稳定;如采用正反馈接法,则其稳定工作状态必为非线性状态。对教学中加入含运算放大器电路接法的教学内容,本文给出一些教学建议。     

运算放大器工作状态的判定及其仿真

运算放大器在工作时具有两种状态:线性状态和非线性状态,分别对应其输入一输出特性的线性区和正、负饱和区.本文讨论了含运算放大器电路中运算放大器工作状态的判定规则,分析了仅引入负反馈含运算放大器电路和同时引入正、负反馈含运算放大器电路的运算放大器工作状态,给出了运算放大器工作在线性区或饱和区的条件.采用OrCAD/PSpice进行仿真验证了分析结果,可供讲授电路课程的教师参考.     

非线性均匀传输线的暂态响应

在实际分布参数电路中,损耗和非线性特性往往同时存在。基于作者的教学和科研经历,本文利用有限差分法数值计算了场效应晶体管沟道这一非线性均匀传输线在高频正弦电源激励下的暂态响应过程,并采用傅里叶级数展开法得到了输出电压含有的谐波幅值。这一内容对于扩展线性均匀传输线知识,加强学生理论联系实际以及综合运用电路知识的能力,均具有较好的推动作用。     

CTIA型读出电路非线性的研究

在红外焦平面阵列读出电路中,其非线性的问题越来越受到重视。读出电路的非线性是产生非均匀性的重要因素,它影响着探测器的灵敏度,限制了探测器的使用范围。文中对电容跨阻抗放大器结构（CTIA）读出电路的非线性进行了理论研究,分析了放大器增益和积分电容对单元电路非线性的影响。同时通过分析源随器结构行选电路,提出采用单位增益负反馈的差分放大器来做行选电路,以提高电路的线性度。     

一种改善CMOSOTA线性度的实现电路

为了满足低电压、低功耗跨导放大器-电容(OTA-C)连续时间型高频模拟集成滤波器结构中,跨导放大器(ITA)对线性度的要求,基于交叉耦合差分对MOS管结构中典型OTA电路的非线性特性进行研究,得到其非线性失真项.据此,提出一种基于前馈线性化原理改善OTA线性度的实现电路,给出线性化处理前后OTA传输特性的对比曲线.结果表明,通过改变结构,提高了OTA的线性度.     

多项式非线性系统多频输入稳态响应的计算

针对工程实际中广泛存在并且有着十分重要应用的一大类非线性电路和系统,即非线性项为幂级数形式的非线性系统,本文称之为多项式非线性系统,提出了一种多频稳态响应的递归化计算方法,将这种非线性系统在多频输入下的稳态响应计算问题化为不断求解同一个线性系统在不同多频输入下的稳态响应,并且基于所构建的算法原理,采用目前广泛使用的Matlab语言编制了通用程序.大量算例表明,本文所提出的方法可以十分有效的用于计算这类系统的多频稳态响应.     

电子线路学习方法(十九) 第十一讲调谐放大器和限幅放大器电路分析方法

一、实用调谐放大器电路分析方法调谐放大器广泛应用于收音机、电视机等电路中,它们中的高频放大器、中频放大器是调谐放大器.虽然收音机、电视机中的高频放大器、中频放大器其信号频率不同,但是其调谐放大的目的和工作原理十分相似.如图1所示是采用LC并联谐振电路构成的选频放大器.初次分析一种电路时先了解电路组成,电路中的VT1管构...     

Generalized Solutions for Optical Maser Amplifiers

The optical maser amplifier is treated from the transient analysis point of view using the Laplace transform method as opposed to the conventional sinusoidal steady-state analysis that sometimes leads to inconsistent results especially for the region beyond threshold. Firstly, the wave equations are expressed in terms of laplace transforms, and then the generalized solutions for both the transmission and the reflection mode of operation are derived taking the transient terms into account. Finallly, the inverse laplace transforms are obtained yielding the generalized solutions in terms of real-time functions. In order to emphasize the point of the argument and also to compare the results of the usual sinusoidal steady-state analysis, use is made of the simplest possible model of a one-dimensional system consisting of three media, air, active medium, and air. An incident coherent transverse electromagnetic wave, which falls normally on the surface of the system, is assumed. The generalized solutions derived agree,in the region below threshold, exactly with that of the sinusoidal steady-state analysis obtained previously by other investigators. However, for the region beyond critical threshold, the generalized solutions indicate that the device goes into a state of self-oscillation with oscillation frequencies that strictly coincide with those of the Fabry-Perot type resonator. Thus, the limitation of applicability of the conventional sinusoidal steady-state analysis is clarified. Some remarks are also given on the design problem of optical maser amplifiers in connection with the transient terms involved.     

Low-Dropout Regulators With Adaptive Reference Control and Dynamic Push–Pull Techniques for Enhancing Transient Performance

An adaptive reference control (ARC) technique is proposed for minimizing overshoot/undershoot voltage and settling time of low-dropout regulators. Linear operation provided by the ARC technique can dynamically and smoothly adjust the reference voltage so as to increase the slew rate of error amplifier thus forcing the output voltage back to its steady-state value rapidly. The amount of transient revision is proportional to transient state output voltage variation and load condition. In addition, a dynamic push-pull technique is used to enhance transient response. Experimental results demonstrate that the undershoot voltage, settling time, and load regulation are improved by 31%, 68.5%, and 70%, respectively, when load current changes between 1 and 100 mA.     

Steady-state analysis of nonlinear circuits with periodic inputs

In the computer-aided analysis of nonlinear circuits with periodic inputs and a stable periodic response the steady-state periodic response is found for a given initial state by simply integrating the system equations until the response becomes periodic. In lightly damped systems this integration could extend over many periods making the computation costly. In this paper a Newton algorithm is defined which converges to the steady-state response rapidly. The algorithm is applied to several nonlinear circuits. The results show a considerable reduction in the amount of time necessary to compute the steady-state response. In addition, the initial iterates give information on the transient response of the system.     

Hartree 近似法研究色散缓变光纤中暗孤子的量子效应

利用含时Hartree近似法得到色散缓变光纤的暗孤子量子非线性薛定谔方程，在一定条件下，有量子态的暗孤子解，并由此方程讨论经典和量子效应对暗孤子传输的影响，由此发现，光场算符的量子力学的平均值是一系列修正的经典孤子的叠加，色散缓变效应等效为一个分布参数放大器的增益。并导致非线性效应增加，使孤子受到压缩。     

Fast periodic steady-state analysis for large-signal electronic circuits

It is shown that current computer-aided circuit analysis programs that are capable of the transient analysis of nonlinear circuits can be modified to include the determination of the periodic steady-state response of large-signal electronic circuits such as class C amplifiers, frequency multipliers, parametric circuits, and oscillators. With this modification only a portion of the transient response is computed, then a Newton iterative technique is used to find the periodic state of the circuit from which the periodic response can be found by a numerical integration over one period. This technique is especially valuable for analyzing high Q circuits and for design purposes where fast analysis is essential.     

Hartree 近似法研究色散缓变光纤中暗孤子的量子效应

利用含时Hartree 近似法得到色散缓变光纤的暗孤子量子非线性薛定谔方程,在一定 条件下,有量子态的暗孤子解,并由此方程讨论经典和量子效应对暗孤子传输的影响,由此发现,光场算符的量子力学的平均值是一系列修正的经典孤子的叠加,色散缓变效应等效为一个分布参数放大器的增益。并导致非线性效应增加,使孤子受到压缩。     

Hartree近似法研究色散缓变光纤中孤子的量子效应

利用含时Ｈａｒｔｒｅｅ 近似法得到色散缓变光纤的量子非线性薛定格方程,在一定条件下,有量子态的孤子解,并由此方程讨论经典和量子效应对孤子传输的影响,由此我们进一步发现,光场算符的量子力学的平均值是一系列修正的经典孤子的选加,色散缓解应等效为一个长距离分布参数的光纤放大器,导致非线性效应增加,使孤子受到压缩     

TNPT-an efficient method to simulate forced nonlinear RF networks in time domain

A new method to simulate forced nonlinear RF networks in time domain is introduced. This method is a generalization of the well-known steady-state algorithm of Trick and Aprille (1972). The proposed method allows one to calculate all time solutions until steady-state is reached similar to transient simulation (TR). It compares with steady-state like TR simulation with DC, and can therefore be considered to be a transient simulation of nonlinear periodic transients (TNPT).     

一种提高DC-DC瞬态响应的误差放大器设计

设计了一种可提高DC-DC瞬态响应的误差放大器,其输出阻抗和补偿电阻随着负载电流的变化动态调整,使系统在不同的负载条件下能够获取足够的相位裕度。同时,设计了采样电路和逻辑选择电路,分别用于检测负载电流变化和选择开关导通。结果显示,采用文中所提出结构,DC-DC的过冲比原来减小了50%。