基于时域线性插值的信号周期计算方法及误差分析.pdfVIP

学兔兔 第32卷 第8期 仪 器 仪 表 学 报 Vol_32 No．8 2011年8月 Chinese Journal of Scientific Instrament Aug．2011 基于时域线性插值的信号周期 计算方法及误差分析 周 峰，赵春宇，黄震宇，陈大跃 (上海交通大学电子信息与电气工程学院 上海 200240) 摘 要：信号周期或信号基波周期的准确测量是周期信号分析的重要环节。基于时域线性插值的周期检测方法是非同步采样 情况下的常用方法，该算法通过计算信号与设定阈值的交叉点间的时间间隔来获得信号周期。插值算法的测量不确定度主要 受到阈值、采样频率和信噪比3个因素的影响，推导出了3个影响因素与测量误差之间的关系式，并进行了理论分析。仿真实 验证明，通过选取信号平均值作为阈值，提高采样频率，利用带通滤波器降低噪声干扰等方法，可有效地减小插值算法测量误 差，提高测量准确度。时域插值算法在谐波分析仪中的应用验证了该算法的实用性。 关键词：周期测量；时域插值算法；误差分析 中图分类号：TN911．6 文献标识码：A 国家标准学科分类代码：510．40 Time·domain linear interpolation algorithm and its error analysis for estimating signal period Zhou Feng，Zhao Chunyu，Huang Zhenyu，Chen Dayue (School of Electronic Information and Electrical Engineering，Shanghai JiaoTong University，Shanghai 200240，China) Abstract：Accurate measurement of the fundamental period of a periodic signal is an important task in periodic signal analysis．Time—domain linear interpolation(TLI)algorithm is a common measuring method，which can be applied in the course of asynchronous sampling．Using the TLI algorithm，the signal period can be obtained by calculating the time interval between adjacent crossing positions where the signal crosses a given threshold；therefore，the measure— ment uncertainty is affected by the threshold，sampling~equency and noise．This paper investigates the relationships between the measurement error and these three critical factors．Simulation results show that the measurement elTors call be reduced effectively and the measurement accuracy can be improved by setting the signal mean value to