Firstly, the existing methods of the three phase power measurement in the teaching materials are introduced. And then another three connection methods are suggested for three phase four wire circuits.

首先介绍了现有教材中已给出的三相电路功率的测量方法，进而提出了三相四线制三相电路功率测量的另三种接线方法。

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The signal pre-processing system also has circuit to extract temperature signal via platinum thermistance, in which three-wire system and constant current measurement method are adopted.

信号预处理系统还包括温度信号提取电路，通过铂热敏电阻实现对温度信号的提取，采用了三线制恒流源测量法。

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