数字频率特性测试仪的设计  

Design of digital frequency characteristic analyzer

作　　者：孙冬娇[1,2] 王文兵[1] 丁俊[1] 

机构地区：[1]南京信息工程大学电子与信息工程学院,江苏南京210044 [2]江苏省气象探测与信息处理重点实验室,江苏南京210044

出　　处：《现代电子技术》2014年第21期73-75,共3页Modern Electronics Technique

基　　金：国家自然科学基金项目(61307061;41275042);江苏省自然科学基金(BK20131001);江苏省高校自然科学研究基金(13KJB510017);南京信息工程大学本科生优秀毕业论文支持计划项目资助

摘　　要：传统的模拟式频率特性测试仪存在价格昂贵、条件苛刻、操作不便和性能指标易受温漂因素影响等不足。针对以上缺点,通过采用数字技术,将先进的DDS和MSP430单片机相结合,集合一些常用的外围模拟电路,设计了一个简易的频率特性测试仪。系统对待测电路的输入信号及其输出响应采样,经数字信号处理后,获得电路的幅频特性和相频特性。设计的测试仪测某RLC网络,中心频率的相对误差小于0.2%,有载品质因数相对误差小于1.25%,最大电压增益大于-1 d B。频率特性测试仪输入输出阻抗均为50Ω,幅频误差绝对值小于0.5 d B,相频误差绝对值小于3°。测试仪能满足一般测试参数需求。In view of the shortcomings of the traditional analog frequency characteristic tester,a simple frequency characteristic tester was designed by means of digital technology,and in combination with the advanced DDS,MSP430 microcontroller and some common peripheral analog circuits. The input signal and output response of the circuit under test are sampled by the system. The amplitude frequency and phase frequency characteristics of the circuit are obtained by digital signal processing. The designed tester was used to test A RLC network. The test results indicate that the system′s relative error of the center frequency is less than 0.2%,relative error of the loaded quality factor is less than 1.25%,maximum voltage gain is larger than-1 d B,input and output impedances are all 50 Ω,amplitude error absolute value is less than 0.5 d B,and phase frequency error absolute value is less than 3°. Tester can meet the testing requirements of general parameters.

关 键 词：幅频特性测试 直接数字式频率合成器 串联谐振 扫频 

分 类 号：TN77-34[电子电信—电路与系统]