增益可控低噪声前置放大器设计  

Design of low-noise pre-amplifier with controllable gain

作　　者：赵德春 王露 白宝平 皮喜田[3] 

机构地区：[1]重庆邮电大学自动化学院,重庆400065 [2]北京华科创智健康科技有限公司,北京100089 [3]重庆大学生物工程学院,重庆400030

出　　处：《现代电子技术》2017年第24期137-140,共4页Modern Electronics Technique

基　　金：国家科技支撑计划课题(2013BAI03B04;2015BAI01B05)

摘　　要：设计一种具有温度补偿、增益可控的低噪声前置放大器。该放大器采用级联放大,每一级通过继电器改变信号通路,从而达到控制增益的目的。在放大器的设计中采用噪声抑制和温度补偿技术,并对原电路使用闭环控制进行优化,既实现了增益可调,增益控制范围为10~60 dB,又保证了良好的增益平坦度和优秀的噪声抑制能力。通过仿真和实际电路波形测试,表明该放大器仅有9μV/℃温度漂移和10 nV/Hz^(1/2)等效输入噪声电压,总谐波失真小于1.2%,能放大μV级DC^50 MHz带宽信号。A low-noise pre-amplifier with temperature compensation and controllable gain was designed. The cascade ampli- fication mode is adopted in the amplifier. The signal channel is changed by means of the relay in each cascade stage to control the gain. The noise suppression and temperature compensation technologies are used in the design of the amplifier. The closed- loop control method is utilized to optimize the original circuit, which can realize the gain adjustability （the gain controlled range is 10-60 dB）, and ensure the perfect gain flatness and excellent noise suppression ability. The results of simulation and practi- cal circuit waveform testing show that the amplifier only has the temperature drift of 9 μV/℃, the equivalent input noise voltage of 10 nV/√Hz and the total harmonic distortion of less than 1.2%, and can amplify the DC-50 MHz bandwidth signal in μV stage.

关 键 词：前置放大器 温度补偿 级联放大 噪声抑制 

分 类 号：TN722[电子电信—电路与系统]