In this paper, some key factors affecting electronic instrument transformers (CSEIT) accuracy, including signal measurement, sampling synchronization, digital signals processing and metrological traceability are analyzed, and the corresponding solutions are also offered. Taken HP 3458A multimeter as measurement system, the paper shows that the selection of reference source transformer, sampling synchronization, merging unit synchronization and digital signal processing technology. Furthermore, the method of multi-filters and DSP fusion is proposed to enhance the accuracy of CSEIT based on off-line character for measurement signals. At the same time, a novel metrological traceability scheme of CSEIT is proposed based on FLUKE 5720A, a multifunction calibrator with an accuracy of one per ten thousand, and BHE-I type. Results of verification show that the designed CSEIT can has higher accuracy and better reliability.%从提高校验系统的精度出发,分析影响校验系统精度设计的几个关键因素,包括信息测量和采样同步技术、数字信号处理技术、设计系统延时和度量溯源等,并提出一些解决技术方案.以八位半的高精度万用表HP3458A作为标准互感器的采集系统为例,分析了信息测量时的高精度采样,采样同步及其与合并单元的同步性等技术实现.进一步基于测量信息可离线分析的特点,提出多数字滤波器和计算算法相结合的信号处理技术,以提高信息测量精度.同时基于校验系统设计方案,提出相对应的比差和相位差溯源分析方案.试验结果显示校验系统具有较高的精度,较好的稳定性和可靠性.
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