无法独立调谐N5242A中的接收器

在我的应用程序中，我理想地将几个“同时”接收器相位测量值进行比率，但我无法这样做，因为我感兴趣的相位信号处于不同的频率，我无法独立调谐N5242A中的接收器
（选项10​​/80/83/400/419/423）在单次扫描期间。
在读到PNA的这个特定模型能够进行相干单通道相位测量之后，我认为有可能在几个扫描的每个感兴趣的频率上进行非比例接收器相位测量，然后将它们进行比率。
作为验证这些非比例测量的行为与我预期的相符或认为他们应该比较使用比例和非比例测量来测量非频率转换设备的群延迟的结果的方法。
第一个测量只包括从某个感兴趣的频段的S21测量中推导出设备的群延迟。
在第二次测量中，我使用N5242A产生双音激励，在设备的输入端具有固定的频率间隔（远大于N5242A的IF BW），然后扫过相同的感兴趣频段。
使用非比例接收机测量，在设备的输出端测量每个音调的相位，具有独立的扫描。
然后使用非比例测量的相位差和两个音调的频率分离来近似群延迟。
由此产生的群体延迟不匹配。
这些测量结果是否会产生类似的结果，或者我对相干单通道相位测量的含义存在一些误解？
感谢您的时间。



     以下为原文

  In my application I would ideally ratio several "simultaneous" receiver phase measurements, but I am unable to do so because the signals whose phases I am interested in are at different frequencies and I do not have the ability to independently tune the receivers in the N5242A (Opt. 10/80/83/400/419/423) during a single sweep. After reading that this particular model of PNA has the ability to make coherent single-channel phase measurements I thought it might be possible to make unratioed receiver phase measurements at each frequency of interest over several sweeps and then ratio them afterwards. As a way to verify that these unratioed measurements behave as I expected them to or thought they should I decided to compare the results from measuring the group delay of a non-frequency translating device using ratioed and unratioed measurements.

The first measurement just consisted of deriving the device's group delay from an S21 measurement across some band of interest. In the second measurement I used the N5242A to generate a two tone stimulus with a fixed frequency separation (much larger than the IF BW of the N5242A) at the device's input that was then swept across the same band of interest. The phase of each tone was measured at the output of the device with independent sweeps using unratioed receiver measurements. Group delay was then approximated using the phase difference of the unratioed measurements and the frequency separation of the two tones. The resulting group delays did not match. Should these measurements have yielded similar results or do I have some misunderstanding as to what is meant by coherent single-channel phase measurements? Thank you for your time.