一种高精度数据采集系统的电路设计

变压器的空载试验中，由于功率因数低，空载电流不是正弦信号，高精度测量其有功功率具有一定的难度。在此应用背景下，对低功率因数含有工频正弦电压波形和工频畸变电流波形的有功功率测量进行了研究，介绍了数据采集系统的电路设计。采用同步采样和准同步采样相结合的双AD通道结构，以AD1674作为模数转换器，使用锁相环作为同步环节。开发出用于PC机的数据采集卡和相应的外围电路，此装置能够满足变压器空载试验的精度要求，已在实际测量系统中使用。

Circuit Design for High Precision Data Acquisition System

In the no-load test of transformer, because of the low power factor and non-sinusoid current waveform, the high precision measurement is difficult.Active power measurement of high precision under low power factor is researched. The two channels AD using synchronous sampling and quasi-synchronous sampling are employed. The AD1674 is used as the AD converter and the phaselocked loop is used in synchronous sampling. The practical data acquisition card and the peripheral circuits used in PC are developed. This system can satisfy the requirements and be applied in practical measurement system.