CAJ | 학술논문

设计并制作一个3 MHz高性能低噪声放大器,以增益稳定、输入低噪声的电压反馈放大器OPA820作为前置放大器,采用二阶低通滤波器实现对3 MHz以上信号衰减,并经功率放大器进行电压及功率放大.为检测低噪声放大器的性能,将功率信号通过隔离、真有效值转换,用AVR单片机进行采集并经LCD显示放大器输出电压有效值和峰峰值.由测试数据可知,放大器的性能优良,电压增益大于40 dB,最大不失真输出电压峰峰值大于10 V,有很强的实用性.
설계병제작일개3 MHz고성능저조성방대기,이증익은정、수입저조성적전압반궤방대기OPA820작위전치방대기,채용이계저통려파기실현대3 MHz이상신호쇠감,병경공솔방대기진행전압급공솔방대.위검측저조성방대기적성능,장공솔신호통과격리、진유효치전환,용AVR단편궤진행채집병경LCD현시방대기수출전압유효치화봉봉치.유측시수거가지,방대기적성능우량,전압증익대우40 dB,최대불실진수출전압봉봉치대우10 V,유흔강적실용성.
A new design of 3 MHz high performance low noise amplifier(LNA) was proposed in this paper.Voltage feedback amplifier OPA820 which has gain stabilization and input low noise is used as preamplifier,second-order low pass filter is adopted to attenuate signal over 3 MHz,and magnify signal through power amplifier.In order to test LNA performance,after power signal isolation and true RMS-to-DC conversion,microcomputer gathers and process data,finally display RMS and peak-to-peak value by liquid crystal display.According to test data,designed LNA has fine performance,voltage gain is no less than 40 dB,and maximum undistorted output peak-to-peak voltage is higher than 10 V.It has strong practicability.