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Siglent SDS800 Zoom out question (problem?)
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eTobey:
Just dropping my signature here.  ;D
Someone:

--- Quote from: electr_peter on October 05, 2024, 10:31:43 pm ---
--- Quote from: Someone on October 05, 2024, 09:16:23 pm ---Why keep bringing up this straw man argument?  :horse:

--- End quote ---
Who is using straw arguments here exactly?
--- End quote ---
There are two straight out lies which are being raised here once again:
Claiming that if you don't blindly capture around the screen then you will have to capture again. Despite that you can capture the entire interesting data without having to capture around the screen.
Saying there is no downside to capturing around the screen. When it does have significant impacts to the trigger/capture system that might cause the user to miss triggers/information.

Repeatedly, over many years. Despite them being completely incorrect. How could its not be clear what I was calling a straw man?


--- Quote from: electr_peter on October 05, 2024, 10:31:43 pm ---@Someone's flawed argument - user always knows best capture settings for each possible signal in advance and can do perfect capture on 1st try. It is not possible for user to select wrong settings, have doubts, second thoughts or additional insights in the process because all is known in advance. Thus no recapture is needed, ever. Thus "zoom out" has no value and can be ignored. Q.E.D.
--- End quote ---
If a user has set their scope to capture around the screen then they have explicitly made that choice (and the downsides it brings), which could equally capture the exact same data by using a longer horizontal sweep. Either way the user had to choose what horizontal capture period they wanted.

The comparison is what those two capture methods trade off, how they compare.

Not some imaginary boogieman/strawman argument of but if you set the scope to capture a short period then you might miss something outside that period. Which applies to either method, the same strawman is equally valid to capturing around the window: what if you didn't set the memory long enough? you'd have to capture again!


--- Quote from: electr_peter on October 05, 2024, 10:31:43 pm ---2N3055's flawed argument - Keysight's "zoom out" should do miracles to get data around already captured on screen data in RUN mode (which in this context is not possible with normal scope). Additional capture around screen occurred later in STOP mode, thus no miracle occurred, thus "zoom out" is not useful.
--- End quote ---
As explained to you multiple times, the benefit of capturing a longer period with every trigger is different to the "bonus"/extra capture when pressing stop on some of the Keysight models. They are not identical or directly comparable/ The use case which motivated capturing around the screen was the end user seeing something of interest and wanting to see the rest of that specific capture around the screen, not some new capture (which is what is collected when pressing stop).


--- Quote from: electr_peter on October 05, 2024, 10:31:43 pm ---Keysight's argument - user should get fast update rate in RUN mode because that's useful (extra memory beyond screen slows down things). User should get maximum memory in STOP mode, because that's logical and user would want that anyway (why limit the user?). So memory settings are reconfigured from RUN to STOP mode automatically. This gives fast update rate in RUN mode & max memory in STOP mode (which also allows zoom out if needed) & user is not limited & no recapture is needed (if user would want to look at data beyond screen).
--- End quote ---
This is where you keep falling down, the additional capture when pressing stop only occurs if there is another trigger after the stop button is pressed. It makes the "recapture" for you, automatic, forced, no choice.

If the user wants to capture that larger period they can do so by setting the horizontal timebase to that at the start.


--- Quote from: electr_peter on October 05, 2024, 10:31:43 pm ---Other scope brand's argument (like Siglent) - automatic modes are too confusing for users and/or too difficult to implement, so let's fix memory to the same size in RUN/STOP modes. User obviously knows in advance what memory settings to choose. It's user fault if scope is slow (too much memory in RUN mode) or there is no data beyond display (not enough memory in STOP mode). It's user responsibility to jump around like a jackrabbit and change settings for optimal performance in RUN/STOP modes.
--- End quote ---
The Siglent scope in question (in the thread title) explains how it sets the memory depth very clearly, it is the horizontal view of the screen. There is no jumping around (or other emotive nonsense) or constantly adjusting things.

If the user wants to capture a particular horizontal period they set that before capturing. Regardless if that is by capturing around the screen, or capturing within the screen. You make the plainly false strawman argument that a user capturing around the screen somehow magically does not choose to do so.

So what should be a relatively simple explanation for this new user is now buried in your massive pile of noise.

So I'll repeat the strawman that you are desperately holding onto:
A user needs to select the period they want to capture before they can reliably capture it (the Keysight "bonus" capture on stop is not going to occur in all situations). Capturing around the screen that length/size/period would have to be set in advance, just the same as if it was set by having a longer horizontal sweep time.

Not different, not some unique benefit of capturing around the screen. Exactly the same.
2N3055:

--- Quote from: electr_peter on October 05, 2024, 10:31:43 pm ---
Who is using straw arguments here exactly? Let's burn some straws:

@2N3055's flawed argument - Keysight's "zoom out" should do miracles to get data around already captured on screen data in RUN mode (which in this context is not possible with normal scope). Additional capture around screen occurred later in STOP mode, thus no miracle occurred, thus "zoom out" is not useful. Q.E.D.


--- End quote ---

This is slander and complete lie. I never said that.
You are now lying and inventing what people said to prove you are right.

I said  Keysight memory management when going into stop is not doing what most people think it does.
And it is useless to "zoom out" from an event on screen because it will show something completely different at random time later after you press stop. And you agree with that. You said it does exactly the same. And that is equivalent to simply changing timebase before pressing STOP. Therefore it is nothing special which results cannot be reproduced by other scopes that don't do that. It is simply reversing an operation: instead of pressing stop and then changing the timebase, you change the timebase and press the stop. At that moment you will have exactly same result in a scope memory.

I have MSOX3104T. For many years now. I had it before I tried any Siglents. I did try LeCroys and have Picoscopes for decades now. None of them does what Keysight does and never I failed to accomplish the task because of that.
I don't use in on Keysight either..
So no matter how much it makes YOU happy that is not something  that should go into making a choice of a scope in any significant magnitude. There are other far more important features to chose Keysight, that one is not the one.
electr_peter:
When did you enter a cult? Do you wear funny hats in meetings? The more you repeat same BS, there more it is obvious you are from a cult for everyone. It is not possible to reason with cult members, it will go over their heads, so this is for external reader benefit only.

Let's define "zoom out" variations properly for once as actual term usage keeps shifting around too much.

"Basic zoom out" - scope's ability to capture beyond screen width in STOP/SINGLE mode when memory length allows, so that user does not get only blank edges if timebase is increased after STOP/SINGLE. This is useful by itself and can be achieved with some scopes in default mode or custom memory setup (how exactly it is achieved is not that relevant). I think this was what Dave alluded mostly in his video.

Keysight's zoom out, aka "zoom out plus" - "basic zoom out" optimized for the max performance, more useful in general. In RUN mode only display is captured, in STOP/SINGLE mode scope captures max memory with new capture or reverts to the last short RUN capture. In other words, it is automatic memory management with idea that user would do the same, as it is logical. RUN mode -> set memory to screen width, thus faster update. STOP/SINGLE -> set memory to max, so more stuff is captured. Or go to wider screen and capture then, it is equivalent. Keysight does that automatically for user.

"zoom out ultra" - same as "zoom out plus", but the very last STOP/SINGLE capture is not new, but the very last short RUN capture, extended to max memory. Extended by miracle or very extensive parallel computation in data acquire path, which is simply not possible with normal scopes in this context.

"zoom out ultra" (which does not exist in normal scopes yet) is set as a benchmark to denigrate any benefits of "basic zoom out" and "zoom out plus", because these are not up to the impossibly high standard.
Nobody is claiming that "zoom out plus" let's achieve something that is not possible by other scopes. Of course not, "zoom out plus" is just clever rearrangement of basic memory length/trigger features (i.e. not magic) to get analysis faster, any scope can achieve equivalent result in other ways.
electr_peter:

--- Quote from: Someone on October 05, 2024, 11:13:36 pm ---There are two straight out lies which are being raised here once again:
Claiming that if you don't blindly capture around the screen then you will have to capture again. Despite that you can capture the entire interesting data without having to capture around the screen.

--- End quote ---
You move around the issue.
If STOP capture was made and was deemed to be too short, then with "zoom out plus" you may not need to make a new capture. With other scopes you do, there is no way out of this situation. Keysight gives you more options, how is that worse?
If STOP capture was at long timebase, no recapture is needed. You can do that with all scopes. But how do you have such insight/luck to do long capture? There we go again with your strawman of "user knows what to capture in advance, thus no need to recapture".
If you call viewing signals in RUN mode capture (or not capture?), then there is no need to recapture(?), just change timebase. Confusing wording in this case.


--- Quote ---Saying there is no downside to capturing around the screen. When it does have significant impacts to the trigger/capture system that might cause the user to miss triggers/information.

--- End quote ---
With "zoom out plus" there are no downsides, none, compared to regular scope approach with equivalent settings. What exactly is captured/not captured depends (as even fast scope has non-zero blind time in fast timebases), but "zoom out plus" is better/comparable (but not worse) in general. "zoom out ultra" would be even better, if it existed.

These so called "lies" fall apart as strawmans/misunderstandings.

--- Quote ---As explained to you multiple times, the benefit of capturing a longer period with every trigger is different to the "bonus"/extra capture when pressing stop on some of the Keysight models. They are not identical or directly comparable

--- End quote ---
Nobody claims that they are exactly identical. Claim is that at similar timebase settings "zoom out plus" feature adds slight advantage over other scopes with no downsides. User can just ignore that and use the scope as it didn't have "zoom out plus" without any difference/downside.


--- Quote ---The use case which motivated capturing around the screen was the end user seeing something of interest and wanting to see the rest of that specific capture around the screen, not some new capture (which is what is collected when pressing stop).

--- End quote ---
To stake all this discussion of such rare corner case and ignore general benefit is laughable. With regular scope you are 100% SOL in this situation. With "basic zoom out" and "zoom out plus" you have very slim chance if anomaly repeats more than once or is longer in duration. With "zoom out ultra" your chances may be better, but that requires miracle functionality. On top of the fact that you somehow managed to stop acquisition at the right time in nanosecond-microsecond ranges of some random signal. Consider yourself lucky. Rethinking of approach is required on case by case basis, "zoom out" is not a magic panacea for all corner cases.
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