微波宽带自动增益控制技术研究

【作者】 李良；

【导师】 唐小宏；

【作者基本信息】 电子科技大学 ， 电磁场与微波技术， 2007， 硕士

【摘要】 随着信息时代的日益发展，人类的生活发生了极大的变化，同时电磁环境也变得日益复杂。在这么纷繁复杂的电磁环境下，要确保通信、雷达、电子对抗等系统的良好运行，是一个越来越受到人们关注的问题。其中接收和发射信号的功率是一个非常重要的影响因素，往往成为一个系统受限的瓶颈。因此系统对功率控制技术的要求也越来越苛刻。另外，带宽也是一个电子系统中非常重要的因素，尤其像在电子对抗这样的宽带系统中，宽带的功率控制就显得尤为必要。本文正是基于这样一个背景，介绍了一种用于接收端动态范围压缩的功率控制技术——自动增益控制(AGC)的系统研究。以及在此基础上，设计完成了一个宽带自动增益控制电路。本文分两个部分，前一部分主要论述了对AGC电路的系统研究(第一章～第三章)，第二部分详细介绍了一个宽带AGC电路的设计与实现(第四章～第六章)。文中第一部分比较了三种压缩动态范围的方法，即自动增益控制、对数放大器和限幅放大器；另外还结合信号处理的方法分析了AGC电路闭环传递函数。以及在此基础上，分析了AGC电路的稳定性问题。第二部分详细描述了宽带AGC电路的设计。其中包含对AGC电路关键器件的设计，用两种方法设计实现一个宽带低噪声放大器；另外搭建延迟式AGC电路，以电调衰减器作为增益可控部件并结合Protel DXP仿真设计其控制电路；在此基础上设计完成30dB动态范围AGC电路；然后结合ADS软件分析和仿真60dB动态范围AGC电路，比较了两种设计方案，并最终确定方案、完成设计以及给出详细实验结果。详尽的系统分析以及结合软件仿真是本课题成功的重要保证，最终设计实现的微波宽带AGC电路指标如下：频率范围为800～4000MHz；动态范围超过52dB；输出功率平坦度小于4dB，输出功率可调，整机噪声系数优于4.1dB。本文的主要特点：设计完成一个宽带AGC电路，带宽达到2.25个倍频程，动态范围超过52dB，取得了较好的技术指标，并且兼顾结构小型化设计。更多还原

【Abstract】 With the fast development of information times, our life has been changed greatly. At the same time, the EM environment has been become complicated increasingly. At the such-and-such EM complicated environment, it’s a big problem which’s got more and more attention that insuring the communication, radar, EW systems well operation. Received and transmitted power level is a very important influencing factor which is always the bottleneck of a system. So our demand for power controlling is more and more rigorous. In addition, bandwidth is also an important factor in electronic systems, such as in the EW system, wide band power controlling is more essential. This paper is based on such background, and introduces a dynamic range compress technology for receiver, automatic gain control (AGC). Along with this base, it gives the design method of a wide band AGC circuit.This paper is divided two parts. The first part mainly introduces the AGC system research (chapter 1～chapter 3). The second part detailedly introduces a wide band AGC circuit’s design and experiment (chapter 4～chapter 6).The first part introduces the structure and working characteristic of AGC, and makes a comparison with AGC, logarithmic amplifier and limited amplifier.The second part describes a real AGC circuit’s design. The design of some important components in the AGC is included, specially using two methods to design a wideband low noise amplifier. Otherwise it introduces the method of design a 30dB dynamic range compress AGC circuit. Then combining ADS software, it gives the 60dB AGC circuit’s simulation and design.Detailed system analyses and comprehensive simulation are the important guarantees for this task. Finally, the AGC circuit’s performances are as follows. BW: 800~4000MHz, over 52dB dynamic range compress, noise figure: <4.1dB. And this design gives attention to miniaturization.更多还原