基于Kaiser窗的相位差校正及tanδ测量应用

Dielectric Loss Factor Measurement Based on Kaiser Window Phase Difference Correction

基本窗函数和广义余弦窗函数对信号加权可减轻非同步采样和非整周期截断对介质损耗因数tanδ测量的影响,但其效果受到窗函数固定旁瓣性能的制约.本文通过分析Kaiser窗函数的主瓣与旁瓣衰减比重可自由选择的特性,提出了基于Kaiser窗的相位差校正的tanδ测量方法,推导了tanδ的计算式,并介绍了基于该算法的测量系统的硬件实现方案.仿真和试验结果表明,Kaiser窗函数抑制频谱泄漏效果好,基于Kaiser窗的相位差校正方法克服了谐波干扰、基波频率波动及白噪声对tanδ测量的影响,且设计实现灵活,测量结果精确、稳定,可用于tanδ的离线测量与在线监测.

The fundamental windows and generalized cosine windows have been used to eliminate the errors of dielectric loss factor tanδ measurement caused by non-synchronized sampling and non-integral period truncation conditions, but the analysis result is restricted by the performance of the fixed side lobes of these windows. The major-Lobe and side lobes＇ characteristics of Kaiser Window are discussed in this paper, and an approach for tanδ measurement based on Kaiser Window phase difference correction is proposed. The arithmetic expression of tanδ is deduced. The hardware implementation for the measurement system based on this approach is described. Simulation and test results show that Kaiser Window function can well restrain spectral leakage, and the influences on tanδ measurement caused by harmonic, fundamental frequency fluctuation and white noise are all overcome with the approach presented. This approach can be designed and realized neatly and has precise and steady results, which can be used in tanδ offline measurement and online monitoring.