转换器的pna-x噪声系数2.4mm E-cal变化

我要尝试的第一件事是设置一个标准的s参数测量通道，匹配噪声系数测量的激励条件，然后使用可疑的2.4mm ECal模块校准该通道。
然后从Response-> Cal-> ECal菜单运行ECal Confidence Check，查看ECal与其存储的工厂数据相比的性能。
如果您发现差异很大，则可能意味着您的ECal需要进行维修和/或重新校准。
你应该比较“好卡路里”和“坏卡路里”的另一件事是每个案例的SC21测量。
ECal在噪声系数校准期间扮演两个角色，一个用于传统的S参数校准标准，另一个用于提供多个阻抗状态以校准噪声接收器增益带宽。
噪声系数cal的S参数校准部分最重要的产品是器件增益（SC21），它基本上构成了噪声系数方程的一半。
因此，如果比较SC21测量的“良好校准”和“坏校准”，差异为.3 dB，那么您就可以确切地知道噪声系数测量中的误差来自何处。
如果要检查并查看噪声接收器的校准情况，最佳可追踪置信度检查是测量校准噪声源的ENR。
您可以通过将噪声源连接到端口2参考平面（校准后）并打开噪声源，直接测量ENR（它是“新建跟踪”对话框下的参数）。
测量的ENR应与测量频率下噪声源的公布ENR相匹配。
但是，在您的情况下，由于您使用的是两个不同的EC，因此IF端口上使用的2.92 mm ECal是用于校准期间提供给噪声接收器的多个阻抗状态的ECal。
但是，使用ENR测量检查作为故障排除工具仍然很有用。



     以下为原文

  the first thing I would try is to setup a standard s-parameter measurement channel matching the stimulus conditions of your noise figure measurement and then calibrate that channel using the suspect 2.4mm ECal module.  then from the Response->Cal->ECal menu run the ECal Confidence Check to see how well that ECal is performing compared to its stored factory data.  if you see a big discrepancy, it could mean that your ECal is due for repair and/or recalibration.  

the other thing you should compare between the "good cal" and the "bad cal" is the SC21 measurement for each case.  The ECal plays two roles during the noise figure calibration, one is for the traditional S-Parameter calibration standard and the other is for providing multiple impedance states for calibrating the noise receiver gain bandwidth.  the most important product of the S-Parameter calibration portion of the noise figure cal is the device gain (SC21) which basicaly makes up half of the noise figure equation.  So if you compare SC21 measured by the "good cal" and the "bad cal", and the difference is .3 dB, then you know exactly where the error in your noise figure measurement is coming from.  If you want to check and see how well the noise receiver was calibrated, the best traceable confidence check is to measure the ENR of a calibrated noise source.  you can measure the ENR directly (it is a parameter under the New Trace dialog) by connecting your noise source to the port 2 reference plane (after calibration) and turning on the noise source. the measured ENR should match the published ENR of the noise source at the measurement frequencies.  However, in your case, since you are using two different ECals, the 2.92 mm ECal used on the IF port is the one used for multiple impedance states that are presented to the noise receiver during calibration.  But using the ENR measurement check is still good to know as a troubleshooting tool.