基于幅-频曲线的系统时域响应特性评价方法

在电磁兼容测量中，通常采用频率响应来描述一个系统的特性。而系统的频响特性一般仅提供了响应幅度的频域分布，很少给出相位信息。在连续波测量时这种幅－频信息是足够的，但在利用频域测量结果评价一个系统的脉冲响应特性时，还必须知道系统的相位信息。本文假设系统为最小相位系统，采用Ｈｉｌｂｅｒｔ变换根据系统响应的频谱幅度估计相位信息，进而将系统的频域信息转换到时域，用于评价系统的时域响应特性。根据一组磁场探头的

Time domain characterization of a system based on the magnitude of its frequency response

In EMC tests, systems are usually described by the magnitude of their frequency responce. Because of the lack of phase information, it is difficult to estimate the time domain characteristics of a system from this kind of data. Aimed to solve this problem, a minimal phase model is proposed to approximate to the real system. Based on the assumption of minimal phase system, the magnitude of frequency response can be related to phase by Hilbert transform. Thus the phase can be reciveved from the magnitude of the frequency response and the impulse response can be estimated. A discrete transfer function model is further used to establish a parametric model for the system, which can describe the system characteristics both in time domain and frequency domain. Examples are given to verify the validity of this method in estimating the phase information for the transfer function of a magnetic filed sensor. Applications of this method in system modeling, signal reconstruction and time domain response predication are also given.