8596E在频段1处显示高衰减但是校准YTF没有

我最近购买了一个8596E，它在0频段完美无缺。在1频段转换时，可以看到额外的27dB损耗。
我已经输入了一个在2.9GHz和3.0GHz之间切换的信号源，它位于0和1频段。频段0幅度点亮，而频段1幅度低27dB。
在梳状信号中可以看到相同的结果。
这是奇怪的事情（但缺乏内部校准的知识）。
如果我运行YTF校准，当梳子的每个支线用于校准时，校准波形在频率进入频段1时显示NO下降。这怎么可能？
由于cal使用实际的分析仪输入，不会排除SYTF或混频器的问题吗？
什么会导致这种巨大的衰减出现在实际使用中，但不会出现在cal中。
该单位偶尔无法完成YTF校准，大多数时候混合器偏置校准失败，无疑是由于此频段1丢失。
谢谢你能解决这个问题。
巢穴



     以下为原文

  I recently acquired an 8596E which performs flawlessly in band 0.

At the band 1 transition, an additional loss of 27dB is seen.

I've fed in a source toggling between 2.9GHz and 3.0GHz which is in band 0 and 1.  The band 0 amplitude is spot on while the band 1 amplitude is 27dB down.  The same can be seen in the comb signal.

Here's the odd thing (lacking knowledge of the internal cal, however).  If I run the YTF cal, as each spur of the comb is used for the cal, the cal waveform shows NO drop as the frequency enters band 1.

How can this be?  Since the cal uses the actual analyzer input, wouldn't that rule out the SYTF or mixer as problems?

What would cause this huge attenuation to appear in actual use but not in cal.

The unit occasionally cannot complete YTF cal and most times fails mixer bias cal, no doubt due to this band 1 loss.

Thank you for any light you can shed on this problem.

Den