低噪声红外人体探测器前置放大电路的设计

在分析了热释电红外传感器输出信号特征的基础上，针对常见红外探测器前置放大电路的缺陷，设计了一种基于AD转换技术、利用MCU进行信号处理的单电源工作双端输出差分放大电路．实验结果表明，该放大电路能有效降低探测器内共模噪声和环境温度波动对输出信号的影响，输出信号频率与幅度体现了人体移动速度、移动方向等信息．

The Design of Preamplification Circuit for Low Noise Human Body Infrared Detectors

W ith regard to the flaw of the preamplification circuit for common infrared detectors ，it proposes the design of a double output differential amplifier circuit after analyzing the output signals of the pyroelectric infra‘red sensor，based on the A／D conversion technology．The amplifier circuit is supplied single power，resorting to the signal processing by MCU．The experimental results show that the amplifier circuit can efectively reduce the influenceof common-mode noise inside the detector and the WaVC motion of environmental temperature on output signals，and that the equency and amplitude of output signals reveal information on the velocity and direction of the human body’s movement．