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What does "Average Type" Refer To in Siglent SVA1032X "BW" Menu ???

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tautech:

--- Quote from: newbrain on September 20, 2024, 07:01:45 am ---The manual, in chapter 2.2.1.4, will tell you what the average types are and what kind of measurements they are best suited for:

Disclaimer: I do not own this instrument, I just read the manual...

--- End quote ---
Later version is here:
https://int.siglent.com/u_file/download/24_05_17/UserManual_UG0703P_E02E.pdf

starlite4321:
Thanks for another response tautech,

Yup, that's the one I've got.  As I mentioned, I just bought it therefore I just downloaded the manual so it's the latest version.

Again, newbrain whose post you quoted here didn't understand the question.  Of course the manual describes what the averaging types are.  And the posts with external references like the one from Keysight just explain the same thing all over again and don't help at all. 

Once again, the question is, what averaging is the "Average Type" setting controlling ?  Where is it happening and how do you TURN IT OFF !!   NOT WHAT AVERAGE TYPES CAN BE SELECTED - which is clearly shown in the manual as keeps being pointed out over and over again.  Because as has been made clear here many times, it's not the "Trace Type" in the Trace menu, and it is not the "Average" settings in the Detect menu.  Because you can turn those off and the "Average Type" setting still affects the trace in the display.  And the type that has been selected is ALWAYS listed on the left side of the display. No setting that I can find turns it off despite what the manual says !

Someone:

--- Quote from: starlite4321 on September 22, 2024, 12:16:25 am ---Because as has been made clear here many times, it's not the "Trace Type" in the Trace menu, and it is not the "Average" settings in the Detect menu.
--- End quote ---
Average detector can use several different "laws", which are selected in the BW menu on these instruments. Where is the confusion?

Do you have any evidence of the result being affected when you change the BW averaging type while the detector is set to the Pos Peak, Neg Peak, or Sample modes ?

shabaz:
Hi,

Inside the spectrum analyzer, there are several locations where averaging "stuff" can occur.

There's one location, near the end of the processing path, called the trace average on most spectrum analyzers. At that location, the trace average can be either:
    * log-power, or
    * power, or
    * voltage mode averaging.

All three are indeed averaging methods. And they are likely to appear in the Bandwidth configuration menu. Consider them as children of the "trace average" function which is the parent.

Those children settings have zero effect on the trace when the parent (trace average) is off.

Keysight/Agilent/HP have a sort of unwritten convention, that many of their spectrum analyzers always display the child averaging type on the screen, regardless of whether the parent "trace averaging" is on or off. The child technically doesn't exist without the parent, but the child type is still displayed. This probably goes back decades, and people don't like changing conventions sometimes even if it doesn't make sense. Please note that I'm speculating, I wasn't around at the time, I've merely used a few SAs and have seen that child value displayed always, it's permanent.

On one of the screenshots in reply #3, the way you'd tell if that trace averaging was enabled, is to see if a number is present in that yellow text I believe (I don't have a Siglent SA). I've reproduced it in the attachment below. You can see the number 94 (yellow arrow in my attachment) and it has not quite reached 100 yet, which is the set value of the number of sweeps for averaging (red arrow). So, the averaging type (LogPwr) in the blue box on the left is valid.

If there was no number in yellow, then that means that the blue box item on the left has no effect. As mentioned, this is convention.

You can test on your spectrum analyzer that this is true, because if trace averaging is switched off, then regardless of that child setting, you'll see no difference on the trace (if you do, then that's a question for Siglent to justify! : ).

So, if you don't want averaging to apply at that location inside the spectrum analyzer, then you'd have to turn off trace averaging, and simply accept that the text is there unfortunately.

tautech:
Thanks shabaz, that's my take on how things work too albeit with only limited SA experience over the last 10 yrs.

The 100 Average screenshot captured at 94 sweeps was entirely intended if nothing more than to show how it removes H&L peaks compared to the other screenshots in that group.

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