宽带测量系统-3 dB通带频率上下限的工程估计

Engineering Estimation of the Upper and the Lower Limits of-3 dBPass Band Frequency of Wideband Measurement System

针对宽带测量系统特点,将测量系统建模为滤波器,形成了标定过程的数学模型。在此基础上推导了滤波器模型-3dB通带频率上限与其标准方波响应前沿、-3 dB通带频率下限与其标准方波响应平顶降的关系式。这2个关系式可用于对实际宽带测量系统-3 dB通带上下限的工程估计。针对实用需求,分析了输入和滤波器模块参数对估计结果的影响,进而给出了工程估计准则。

In this paper,the wideband measurement system is modeled as a filter calibration procedure,and a mathematical model of time-domain calibration process for broadband measurement system is established.Both the upper limit of-3 dB pass band frequency and the rise time of standard square wave response of filter model and the lower limit of-3 dB pass band frequency versus the flattop declination standard square wave response are deduced.Based on this,the upper and the lower limits of pass band frequency of broadband measurement system can be estimated.The effects of input and filter module parameters on the estimation results are analyzed,and then the engineering estimation criteria are given.