本文介绍一套用于线性系统传递函数辨识的程序块—IDENT 块,它是控制系统计算机辅助设计软件包中的一个重要组成部分,本程序块可以处理现场记录的三种不同数据:①由频率特性测试仪或其它频谱分析仪所获得的频率特性数据;②由相关分析仪获得的脉冲响应数据;③由记录仪获得的输入输出信号随时间变化的数据,因此适用范围较广,不仅可用于离线辨识,而且可用于在线辨识。另外,为满足辅助设计软件包后续程序块—仿真程序块等设计程序块的需要,IDENT 块可以提供两种形式的模型:传递函数或脉冲传递函数。本文对程序块中的四个主要子程序—数字积分程序、曲线拟合程序、最小二乘程序及双线性变换程序作了介绍,并给出了应用该程序块对一个电液伺服系统进行辨识的实例。 This paper presents a set of block-IDENT blocks for linear system transfer function identification. It is an important part of the CAD software package of the control system. The block can handle three different kinds of data recorded in the field: Tester or other spectrum analyzer to obtain the frequency characteristics of the data obtained by the relevant analyzer pulse response data obtained by the recorder input and output signals over time data, so a wide range of applications, not only for offline Identification, but also for online identification. In addition, IDENT block can provide two kinds of models: transfer function or pulse transfer function to meet the need of design block such as simulation program block in assistant design package. In this paper, the four main subroutines in program block - digital integral program, curve fitting program, least square program and bilinear transformation program are introduced. The application of this program block to an electro-hydraulic servo system Identified examples.