用于传递函数参数辨识的改进复向量拟合法  

Improved Vector Fitting Method for Parameter Identification of Transfer Functions

作　　者：张黎[1] 李庆民[1] 王伟[1] Siew W H 

机构地区：[1]山东大学电气工程学院,济南250061 [2]英国Strathclyde大学电机系,Glasgow,G1 1GW,UK

出　　处：《高电压技术》2008年第8期1542-1546,共5页High Voltage Engineering

基　　金：国家自然科学基金(50577039)~~

摘　　要：一般电磁场天线的幅频特性并不平坦,必须建立其等效传递函数对测量数据进行数字化校正,才能正确归算出实际的电磁干扰强度。为此,在传统的复数向量拟合法的基础上,通过增加导数信息以及将系数矩阵右乘一个对角阵,提出了一种改进的复数向量拟合法。由于导数可反映数据的局部变化率,因此加入导数元素的系数矩阵,理论上可包含更多的被拟合曲线的高阶信息和局部细节;而将系数矩阵右乘一个对角阵是为了进一步降低方程条件数从而提高计算精度。仿真和应用结果表明,改进算法较之传统复数向量拟合法,可更好地逼近实测幅频特性曲线的局部细节,具有更高的拟合准确度,并在一定程度上降低对频域采样点数的要求。Due to the non-flat amplitude-frequency characteristics of the antennas used in electromagnetic compatibility measurement, it is necessary to establish the equivalent transfer functions of the antennas so as to make digital correction to the measured data, from which the actual electromagnetic interference can be traced back. Based on the previously available vector fitting methodology, with introduction of the first-order derivative and right-multiplication to the coefficient matrix by a diagonal matrix, the paper presents an improved vector fitting methodology. Since derivatives can reflect the local change rates of the data, the coefficient matrix with derivative elements can comprise more high-order information and local details of the curve to be fitted. In the meantime, the right-multiplication to the coefficient matrix by a diagonal matrix is aimed to reduce the influence of condition number so as to improve the calculation accuracy. Simulation and application show that, the improved methodology can approximate better the local details of the actual frequency response curve and renders higher fitting accuracy than the general vector fitting method does, and to some extent reduces the requirements of sample number in the frequency domain.

关 键 词：传递函数 参数辨识 电磁场天线 复向量拟合法 超定方程组 数字校正 

分 类 号：TN03[电子电信—物理电子学]