前置低噪声放大器的研究与设计  

Research and design of the low noise preamplifier

作　　者：王秀华[1] 

机构地区：[1]兰州交通大学自动化与电气工程学院,兰州730070

出　　处：《电子测量技术》2013年第6期35-37,共3页Electronic Measurement Technology

摘　　要：为了检测传感器输出的微弱信号,使用分立元件设计了一种低噪声前置放大电路。对比运放放大电路,详细分析了影响双极型晶体管输入电压噪声密度的参数,其中Icmax和rbb对电路性能影响较大,根据这些参数及多级放大器噪声理论设计了电路。分析了电路结构,并根据不同使用场合给出了不同的改进建议。给出了幅频特性和噪声密度曲线,仿真和测试均证明本电路噪声密度低于1nV(Hz)^(1/2),具有一定的应用价值,可用于对噪声特性要求较高的微弱信号测试仪器中。To detect the small signal of the sensor designed a low noise preamplifier by unattached components.Comparison with the amplifier by op detailed analyses the parameters of bipolar transistor about input voltage noise density.Icmax and rbb are the two important parameters.Based on these parameters and multilevel amplifier theory designed this preamplifier.Analyses the structure of this circuit and gives several improved suggestion in different using fields.Amplitude-frequency curve and noise density curve are given.Simulation and testing both show the noise density is lower than 1 nV（Hz）^（1/2）.This circuit can be used in the instruments of small signal.

关 键 词：双极型晶体管 低噪声放大器 噪声密度 

分 类 号：TN7[电子电信—电路与系统]