2013年全国大学生电子设计竞赛射频宽带放大器（D题）2013年9月7日摘要随着信息化时代的到来，对于高频宽带放大器的要求越来越高。本设计采用STC89c52为控制核心，两片可控增益放大器VCA822为主放大器，后级AD8009为构成了放大主电路，实现了宽带可控增益的射频放大器。VCA822对前级输入信号进行程控放大，后级AD8009射随输出以达到功率要求，并且进行了阻抗变换。单片机和按键，显示模块实现数控增益，人机界面好。为降低纹波干扰，提高信噪比，设计了高精度低纹波线性电源给放大电路和单片机供电。整个系统稳定性强，干扰能力强。本系统制作简单，经测试能达到题目要求。关键词：高频宽带放大器、单片机、STC89C52、OP820、AD8009、VCA822AbstractWith the arrival of the information age, the high-frequency broadband amplifiers have become increasingly demanding. This design uses STC89c52 as the control center, two controllable gain amplifier VCA822 main amplifier, after the class AD8009 as constituting an enlarged main circuit to achieve a controllable gain broadband RF amplifiers. VCA822 on pre-programmed input signal amplification, after AD8009 emitter follower output stage to achieve the power requirements, and conducted a impedance transformation. SCM and buttons, the display module digitally controlled gain, man-machine interface. To reduce the ripple i