针对目前电子科研实验室缺乏低成本音频扫频仪的现状,设计了一种基于虚拟仪器的数字音频扫频仪.系统主要由数字信号处理器最小系统、低通滤波电路、待测网络、抗混叠滤波电路以及上位机控制界面组成.阐述了用于扫频信号产生和幅频特性测试的算法.现场测试数据表明,系统能够在容许误差范围内测出待测网络在音频范围内的幅频特性,证明了系统设计方案的合理性,同时也证明了虚拟数字音频扫频仪可能成为今后数字音频扫频仪的发展趋势.%Aiming at the current status that the electronics scientific laboratories lack the low cost audio frequency sweepers, the digital audio frequency sweeper based on virtual instrument is designed. This system is mainly composed of the minimum system of the digital signal processor, low-pass filtering circuit, network to be measured, anti-aliasing filtering circuit and host computer control interface. The algorithms used for generating frequency sweeping signals and testing the amplitude-frequency characteristics are described. The field test data indicate that the system design scheme is reasonable, and the amplitude-frequency characteristics within audio frequency range of the network to be measured can be obtained under tolerated error, meanwhile, this scheme mostly would be the development trend of digital audio frequency sweepers in the future.
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