温度传感器校准系统中红外信号检测电路设计

Design of infrared signal detection circuit in a temperature calibration system

为了提高红外探测器检测红外微弱信号的精度,采用晶体管恒流偏置电路,使用低噪声高速运算放大器构成了前置放大电路。运用电路理论建立放大电路的噪声等效模型,采用叠加法计算1级放大输出端的噪声电压。通过中温黑体炉红外辐射实验,测试电路性能,取得了500℃～700℃时的电压波形,计算得出信噪比为7.25×103。结果表明,红外探测器前置放大电路达到高信噪比、响应速率快、抗干扰强的应用要求,可以对红外微弱信号检测放大。

In order to improve the accuracy of infrared detectors to detect the infrared weak signal, a preamplifier circuit was built with a constant current bias circuit and a low-noise high-speed operational amplifier. The equivalent noisy model was deduced based on the circuit theory. The output vohage noise of the 1 st amplification circuit was calculated with the superposition method. In temperature blackbody furnace experiment, the circuit performance was tested, the voltage waveform at 500℃- 700℃ was obtained, and signal-to-noise ratio of 7.25×10^3 was obtained. The results show that the preamplifier circuit of infrared detection achieves the application goal of high signal-to-noise ratio, response speed and strong anti-jamming performance, it can be used to amplify the weak infrared signal.