传感器微弱信号低噪声斩波放大器

The Low Noise Chopper Amplifierfor Sensors Weak Signal Amplification

本文介绍一种实用的传感器微弱信号低噪声斩波放大器.它由精密绝对值(整流)电路、电斩波放大电路和低通滤波电路三部分组成,适用于传感器或经一级前放输出的微弱波动信号需直观地由其直流电压正幅值来反映其变化的场合.输入信号即使只有几十微伏或几百微伏此放大器都能正常工作,而且在红外测温判别产品质量方面应用效果良好,获得了激光加热工件时靶点温升温降的红外热谱曲线.

This article presents a pratical low noise chopper amplifier for sensor s weaksignal amplification. It is composed of precise absolute value (rectification)electric cir-cuit,chopped wave amplifier and low-pass filter electric circuit. It processes the weak,upand down (positive and negative)oscillating signal from sensor or one stage preamplifi-er,so that it reflects the probed objective physics directly perceived through the sensesby the positive direct current volt range. The 1ow noise chopper amplifier is novel andworkable,even though the input signal has only tens or hundreds microvolt and it stillworks well. And it is useful in infrared thermal testing,the effect is fine: By using thelow noise chopper amplifier,we get the infrared thermal signal wave.of the temperaturechangs of the sample while it is heating by a laser.