基于NTC的非平衡桥式测温电路的误差分析

针对基于光腔衰荡光谱(CRDS)技术的痕量气体检测技术中对DFB激光器波长稳定性的要求，以EPM1654型激光器模块为例，对基于NTC热敏电阻的非平衡桥式测温电路进行了深入分析。对无源电阻器件的标称值误差和温漂、有源运算放大器的失调电压和温漂、AD转换器的噪声和量化误差、热敏电阻阻值 温度非线性拟合等环节造成的测温误差进行定量分析和权重比较，得出桥臂参考电阻的标称值误差和温漂为影响测温精度的首要因素。同时通过对选取不同桥臂参考电阻阻值时的测温精度进行比较，发现选择使用环境温度范围内与NTC热敏电阻阻值相近的参考电阻有助于减小测温误差。

Error analysis of unbalanced bridge circuit based on NTC

Focused on trace gas detection technology based on cavity ring down spectroscopy in the DFB laser wavelength stability requirements,taking EPM1654 laser module for example, the unbalanced bridge circuit for temperature measurement based on NTC thermistors is deeply analyzed. The guantitative analysis and weights comparison of the temperature measurement error caused by a variety of factors, which include the nominal value of the error and drift of passive resistance of the device,the active operational amplifier offset voltage and drift,noise and quantization error of the AD converter,thermistor resistance temperature nonlinear fitting,shows that the nominal value of the reference resistor error and drift is the primary factor affecting temperature measurement accuracy. By the comprision of temperature measurement accuracy of differernt bridge reference resistior,we find that within the ambient temperature, the NTC thermistor which has the similar resistance to the reference resistarce helps to reduce measurement error.