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Later, it makes some comparison with four kinds of modulation technique, and finally, it implements the three-level PWM switching power amplifier with the PWM technique. The power of the amplifier is 2kVA, and the frequency bandwidth is 10～3kHz. In the thesis, the author designs and makes the hardwares of the switching power amplifier. The hardwares contain power inverter rank circuit, control system circuit based on DSP, drive and isolation circuit, and protective circuit. The thesis also analyses the potential safety problems and put forward some solutions for the problems. Furthermore, the thesis accomplishes the software design of the control system, and successfully debugs it. The methods of designing higher power ampilfier are also discussed in the thesis. It analyses the feasibility of the methods, outlines the way of how to design higher power switching power amplifier, and does some experiments with the method of switches-parallelling.

根据电动振动试验系统对开关功放的要求，提出了以电感电流瞬时值控制技术为基础的三电平脉宽调制开关功放的设计方案，并通过系统仿真进行了原理性论证；然后设计并制作了开关功放的硬件，包括功率转换电路，基于DSP的控制电路，驱动、隔离电路以及保护电路；针对开关功放数学模型不易得出的特点，细致分析了模糊自适应PID控制方法，在此基础上编写了控制程序；研制出一台功率为2kVA，通频带为10～3kHz的三电平脉宽调制开关功放；论文中还探讨了实现大功率开关功放的方法，分析了各种方法的可行性，给出了实现大功率开关功放的思路，并进行了并联开关管实现大功率开关功放的实验。

For weak nonlinear distortion, the expressions of total harmonic distortion, the second order intermodulation distortion(IM2 ), the third order intermodulation distortion(IM 3) and intercept point(IP 3) are deduced. With the aid of software Multisim, we simulate transistor common emitter amplifier, transistor common emitter amplifier with resistor in emitter, differential amplifier and differential amplifier with resistor between emitters. The simulational results and theoretical analyses are almost the same.

针对弱非线性失真，推导了总谐波人、二阶互调失真( IM2 )、三阶互调失真( IM3)和截点( IP3)的表达式，借助于 Multisim软件，对晶体管共发放大器、发射极带反馈电阻的失发放大器、差分放大器和发射极间带反馈电阻的差分放大器进行了仿真，并与理论结果作了比较，结果令人满意。

When the beam current is below free-running start oscillation current, the results of the nonlinear simulation are consistent with the results of the amplifier's linear theory.

本论文所探讨均匀与非均匀半径结构的磁旋返波管，模拟结果显示操作电流低於自由起振电流非线性分析结果符合放大器线性理论，属於amplifier的操作区段。

The invention discloses a DC/DC circuit, comprising a PWM controller, a current amplifier, a peak current comparator, an error amplifier, a main switch, a synchronous switch and also an operational amplifier. The non inverting input end of the operational amplifier is used for coupling with input voltage or voltage reference, or used for coupling with the input voltage and the voltage reference; the inverting input end of the operational amplifier is used for coupling with the voltage reference or ground, and the output end thereof is connected with the non inverting input end of the error amplifier.

本发明公开了一种DC/DC电路，包括PWM控制器、电流放大器、峰值电流比较器、误差放大器、主开关和同步开关；还增设运算放大器，其同相输入端用于与输入电压或基准电压耦合，或用于同时与输入电压和基准电压耦合；其反相输入端用于与基准电压或地耦合，其输出端与所述误差放大器的同相输入端连接。

S1 is then changed to position 1. The voltage stored on C1 is inserted between the output and inverting input of the amplifier and the output of the amplifier changes by VIN to maintain the amplifier input at the input offset voltage. The output then changes from (VOS + IbiasR2) to (VIN + IbiasR2) as S1 is changed from position 2 to position 1. Amplifier bias current is supplied through R2 from the output of the amplifier or from C2 when S1 is in position 2 and position 1 respectively. R3 serves to reduce the offset at the amplifier output if the amplifier must have maximum linear range or if it is desired to DC couple the amplifier.

接着 S1 拨到位置 1，使 C1 的电压加在放大器的输出端和反相输入端之间，(由于电容端电压不能突变，所以)输出端的电压将产生大小等于 VIN 的变化，使放大器输入端维持输入失调电压，即当开关 S1 从位置 2 拨到位置 1 时，输出端电压将从(VOS + IbiasR2)变为(VIN + IbiasR2)。S1 处于位置 2 时，放大器的偏置电流是由输出端经电阻 R2 提供的，当 S1 转向位置 1 时则由 C2 提供。R3 的作用是降低输出失调电压，如果要求放大器具有最大的线性范围，或者采用直流耦合，就应该使用该电容。

This kind of technology can flex the application of optical amplifier so that a same adaptive amplifier can be used as a pre-amplifier, a boost amplifier as well as a line amplifier.

在光标记交换系统中，可满足由于路由切换导致的光功率损耗大范围动态变化的应用需求。

In this report we shall apply this methodology to the operational transconductance amplifier based high frequency design.

在本计画中，除了将他的方法应用在运算转导放大器(Operational transconductance amplifier)为主的高频滤波器，我们也提出一个在Z领域上处理侦错、诊断及容错的方法。

Mobile phone RF system consists mainly of transceivers, power amplifier and antenna switch. PA might be set in the Front-End-Module or FEM. In 2G, the cost of RF system was only about US $1.5, while In 3G, the cost was increased to between US$6.0 and US$8.0, and the cost will further increased to about US$8.0 to US$10.0 in 4G, obviously, FR system had the highest cost growth during the upgrading of mobile phones.

手机射频系统有三个主要零组件，收发器、功率放大器（Power Amplifier，下简称PA）和天线开关，有时PA包含在前端模块（Front-End-Module，简称FEM）。2G时代的射频系统只占大约1.5美元的成本，3G时代则占大约6-8美元的成本，4G时代则占大约8-10美元的成本，也是手机升级换代成本增加最多的部分。

Operational Tran conductance lifers and Grounded actorhas become one of the most important methods to implement integrated continuous-time filters. Operational Tran conductance Amplifierscan transfer input voltage into current to output,and control or change output current within large range by an external controlling current of amplifier. Most articles consider OTA as a voltage-mode circuit component and give voltage-to-voltage transfer function of all having been implemented filter circuits,i.e. The input signal and output signal of filter circuits are voltages .

运算跨导集成运算放大器OTA ( Operational Tran conductance Amplifier 以下简称跨导运放)的功能是将输入电压转换为电流输出，并通过外加偏置电流控制运放的工作电流，从而使它的输出电流在较大范围内变化，而在大多数文献中，器件都被作为电压模式元器件使用实现的各种滤波电路都是按传送电压比给出的，即滤波电路输入信号和输出信号均为电压信号。

In the first part of the thesis, we propose and investigate experimentally a gain-clamped S-band erbium-doped fiber amplifier, a stable and single-longitudinal-mode oscillation of an S-band EDF ring laser. The behaviors and performances of the S-band amplifier have also been discussed in the text.

本论文的第一部分是提出一个S频段的增益箝制掺铒光纤放大器（Erbium-Doped Fiber Amplifier： EDFA）与一 S 频段的单模光纤回路型雷射。S频段的增益箝制EDFA的光特性与其行为都在本文中被探讨。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。