Hello,
This is regarding detector modes in PXA Spectrum analyzer mode.
Under detector menu, we have the "Average " option with "Log/RMS/V". This average mode is selected under measurement set up "Average type".
Let us say, I have selected average detector with Average type RMS. Here the RMS averaging is done for the sample points in the bucket and the log of this data is displayed (I am in the log display mode). Now I am doing a trace average with 10 count. Here each trace point data is averaged with the next trace point data (RMS value of each trace point) and the average is displayed.
Now let us say, I have selected "Average" detector with "Log" average mode. Here Log of each sample in the bucket is averaged and the average is displayed for the bucket.With trace averaging, each trace point is averaged and the average is displayed.
In the R&S analyzers, we can select the RMS detector and for trace averaging, log/lin/power options are there. I am not able to releate this with way agilent is et up. Appreciate your comments.
This is regarding detector modes in PXA Spectrum analyzer mode.
Under detector menu, we have the "Average " option with "Log/RMS/V". This average mode is selected under measurement set up "Average type".
Let us say, I have selected average detector with Average type RMS. Here the RMS averaging is done for the sample points in the bucket and the log of this data is displayed (I am in the log display mode). Now I am doing a trace average with 10 count. Here each trace point data is averaged with the next trace point data (RMS value of each trace point) and the average is displayed.
Now let us say, I have selected "Average" detector with "Log" average mode. Here Log of each sample in the bucket is averaged and the average is displayed for the bucket.With trace averaging, each trace point is averaged and the average is displayed.
In the R&S analyzers, we can select the RMS detector and for trace averaging, log/lin/power options are there. I am not able to releate this with way agilent is et up. Appreciate your comments.
There are differences between what Agilent and R&S call their detectors, and probably how the automatic coupling is done.
Agilent has an Average detector, and you can chose the Average Types of Log power (video), Pwr Average (RMS) or Voltage avg.
R&S has an RMS detector, and you mentioned they have trace averaging selections such as Log, etc.
On the PXA, if you chose the Average Detector, we automatically couple to the RMS detector type. This is done because this combination provides accurate signal amplitude *and* noise measurements. We are taking the “log of the averages”
If you had a situation where the a CW signal was very close to the noise floor, and you wanted to “pull” the signal out of the noise so you could make a good measurement of the signal, you could chose Average detector and Average Type Log “the average of the Log”, and this combination would cause the noise to be under reported (the noise floor would decrease). You could make an accurate CW signal measurement but not an accurate noise measurement. Some people may want to do this, but they need to understand what the risk is and that the “log of the averages” is not equal to the “average of the Log”. Obviously if your signal of interest is a noise-like comms signal, you would not want to select Average detector and Average Type Log.
Regards -