根据调幅广播发射机载波振幅变化指标的定义，通过对调幅信号的频谱进行分析，提出了一种对调幅发射机载波振幅变化指标的测试方法。该方法不再需要用量热法测量功率，只需用频谱分析仪测量载波电平的变化，通过简单计算即可得到载波振幅变化。利用GUM方法对测量不确定度进行了分析，介绍了评定测量不确定度的步骤和一般流程，分析了此测量方法的不确定度来源，并按照实际测试环境对不确定度进行了评估，对在不确定度评估中需要注意的几个问题进行了说明。%Based on the definition of the carrier amplitude variation,this paper presents a test method for carrier amplitude variation of an amplitude⁃modulation broadcast transmitter according to the analysis on AM signal spectrum.In this method,the result can simply be derived from the carrier level variation read from the spectrum analyzer instead of measuring power in calorimetric method.Besides, this paper analyzes the uncertainty of the test method by GUM,consisting of the following parts: first of all,the general processes of assessing the uncertainty of measurement are introduced;secondly, the uncertainty sources of the method are analyzed and then the uncertainty is evaluated under the test environment;finally,several points for attention during the uncertainty evaluation are illustrated.
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