简易数字控制宽带放大器的设计与实现

设计一种数字控制的高增益宽带宽放大器，提出了采用多个放大器直接耦合级联方式，通过理论分析合理选择各级增益的分配，明显改善了放大器的低频特性，极大地提高了增益范围。系统由前置放大电路、程控增益放大电路、通频带选择电路、功率放大电路、单片机控制电路以及电源模块6个部分组成。其中通频带选择电路由两路巴特沃斯低通滤波器组成，可实现通频带的切换；功率放大电路由多个高速缓冲芯片BUF634并联组成，扩大了电流输出范围，实现了功率放大；单片机控制电路以MSP430G2553为主控芯片，使用液晶12864实现显示功能，人机界面友好。经测试，本系统能够完成0~10MHz频率范围内的0~80dB增益步进可调功能。在增益为60dB时，输出电压噪声峰峰值小于0.3V，很好的完成了系统的设计指标。

Design and Implementation of Simple Digital Control Broadband Amplifier

A digital control and high gain wide bandwidth amplifier is designed. Direct-coupling cascade mode with multiple amplifiers is proposed, and reasonable selection of the distribution of gain at all levels is analyzed through theoretical analysis, and it greatly improves the low frequency characteristic and greatly improves the gain range of the amplifier. The system consists of six parts: the preamplifier circuit, programmable gain amplifier, filter circuit, power amplifier circuit, single-chip microcomputer control circuit and power supply module. The general frequency band selection circuit is composed of two channels of Butterworth low-pass filter, and can realize the switching of the frequency band. The power amplifier circuit is composed of a plurality of high-speed buffer chips BUF634 parallel, and can enlarge the range of current output and realize power amplifier. Single chip microcomputer control circuit takes MSP430G2553 as the main control chip, and the system use LCD 12864 to achieve the display function, so it has friendly man-machine interface. The system can accomplish from zero to eighty dB gain step adjustable function during zero to ten MHZ frequency range through testing. When the gain is 60 dB, the output voltage noise peak-peak is less than 0.3V, so it is very good to complete the design index of the system.