程控低噪声宽带直流放大器设计

摘要

To solve the problem that small signals are easily disturbed and difficult to be amplified,a low noise and wideband direct current programmable amplifier is designed with the single-chip computer MSP430F247 as the control core,and with voltage-controlled variable gain wideband amplifier VCA820 as a programmable gain amplifier.The signals from 0Hz to 20MHz can be programmably amplified from the range of 0dB to 80dB with the step of 1dB.The in-band gain variation is less than 0.5Db.The signal peak-peak value of 50 ohm load output is up to 30 volts.The system is of small zero drift,wide bandwidth,high-driven capability and stable performance.This design can be widely applied in communications equipment and sensor networks.%为解决小信号易受干扰、难以实现线性放大的问题,以MSP430F247单片机为控制核心,采用压控可变增益宽带放大器VCA820作为程控增益放大器,设计了一个低噪声宽直流放大器.系统能对直流到20MHz的信号,实现增益从0dB到80dB范围内以1dB为步进的程控放大,带内增益起伏小于0.5dB,50负载时输出信号峰-峰值高达30V.系统的零点漂移小,工作带宽高,驱动能力强,性能稳定,可广泛应用于传感器网络和通信设备等电路中.