Nowadays, the main architecture of distributed airborne testing system is the PCM and Ethernet testing system. Time delay in airborne test system affects the real-time, accuracy and efficiency quality of the acquisition system. The basic knowledge of distributed PCM and Ethernet airborne system are firstly described, then given the method of how to test the delay, and taken an experiment on the two different systems which using a same analogy signal. Finally through the analysis of the experimental results, the airborne test system is made of some suggestions to configure.%目前分布式机载测试系统主要采用PCM和以太网的体系架构,机载测试系统的时间延迟影响着数据采集的实时性、准确性和高效性.在介绍基于PCM和基于以太网分布式机载测试系统的基础上,分别给出了PCM、以太网架构下系统基于模拟量的时延测量方法；并针对同一模拟量信号分别在PCM和网络分布式机载测试系统下对其时延进行了测量,并对实验结果进行了分析.同时根据实验结果对机载测试系统的配置和应用方面提出了一些建议.
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