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本文对低噪声行波管噪声系数的量测问题进行了分析讨论。比较了不同的量测方法， 并对其误差进行了详细的定量分析，指出误差的主要来源有以下几项： １．噪声源额定噪声输出的校准误差。 ２．精密衰减器的校准误差和运用时的失配误差。 ３．接收机噪声引起的误差。 ４．稳定性与重复性不良引起的误差。 本文通过分析给出了定量计算上述各误差方程和计算曲线，从而可以方便地 计算出不同量测条件下的总误差。 分析的结果表明，采用木文所具体介绍的方法，（只用常用仪器而不采用超低温装 置等特殊设备）在量测（２～１５）ｄｂ的噪声系数的范围内，可以使总误差不大于± （０．３～０．５）ｄｂ。 简要地介绍了在降低误差方面所进行的关键性实验工作，在Ｓ小段，量测（８～１５） ｄｂ的噪声系数时，（若增益为２５ｄｂ左右），目前达到了总误差不大于±０.６ｄｂ的 准确度。
In this paper, the measurement of low noise traveling wave tube noise figure is analyzed and discussed. Different measurement methods are compared and their errors are analyzed quantitatively in detail. The main sources of error are as follows: 1. Calibration error of noise source rated noise output. 2. Precision attenuator calibration error and mismatch error when using. 3. Receiver noise caused by the error. 4. Stability and repeatability caused by poor error. In this paper, the quantitative calculation of the above error equations and calculation curves are given, which can easily calculate the total error under different measurement conditions. The results of the analysis show that using the method described in detail in the text (only using special instruments instead of special equipment such as ultra-low temperature devices) can make the total error not greater than ± (0.3 ~ 0.5) db. Briefly introduced the key experimental work in reducing errors, in the S-segment, measuring (8 ~ 15) db noise figure, (if the gain is about 25db), the current total error is not greater than ± 0 .6db accuracy.