基于低速采样的虚拟频率特性测试仪设计与实现

摘要

Traditional frequency characteristic tester is far from satisfactory in calculation and analysis capability,as well as the price and portability.A virtual frequency characteristic tester is designed for wideband circuit networks based on upper and lower machines.Utilizing frequency down-conversion technique in the communication technology,the lower machine turns the frequen-cy response of the circuit under test into DC signals to acquire the wideband information at a low rate.The USB interface is ap-plied to connect the upper computer with the lower one.A virtual instrument soft panel is developed to calculate and analyze the data from the lower machine using Matlab software.The experimental results demonstrate the validity of the proposed scheme.%针对传统频率特性测试仪计算和分析功能不强、价格昂贵、携带不便等问题，设计了一种基于上、下位机的宽带电路网络虚拟频率特性测试仪。下位机借鉴通信中的下变频技术，将被测电路的正弦响应信号下变频成直流信号，以低速采样实现对宽带信号的采集功能；上位机通过 USB 接口与下位机进行通信，采用 Matlab 软件设计虚拟仪器软面板，实现了数据计算、分析与显示功能。实验结果验证了方案的有效性。