Products > Test Equipment
Oscilloscope Zoom Out Quirk
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Wuerstchenhund:

--- Quote from: SilverSolder on May 11, 2020, 01:35:28 pm ---It seems a bit harsh, to tell the photographer that if he didn't get the zoom factor exactly right before looking in the viewfinder, he must be badly prepared...   That isn't how everybody thinks.
--- End quote ---

Then go and ask any professional photographer if he really prefers having to determine the exact position on scene with no way to change it later without a notable loss of quality, and if it the original decision turns out to be wrong to have to go back to the actual place of scene and re-take the shot, over just being able to capture some excess and then decide later in his lab on which segment he wants to have in the image (and being able to play with different sizes and individual objects on his computer). It's a no-brainer, really.

The *only* thing preventing this is the unavoidable loss of resolution (i.e. detail) that comes with taking a 'zoomed out' wide shot of the whole scenery and then 'cutting out' the interesting objects in separate images. WHich comes from the fact that the sensor resolution is fixed and when "zoomed out" that fixed resolution has to cover a larger scene area, thus resulting in a lower resolution per scene area than when zoomed in.


--- Quote ---Some people like "bump and feel" parking...   if that was what we were talking about, I'd agree with you!  - but using the zoom flexibly if the instrument supports it, seems to be just making good use of the tool.
--- End quote ---

The thing is, he's *not* using the zoom, he's using post-acquisition timebase changes purely for the purpose to avoid using the zoom function, as it seems mostly because his scope (if I had to guess I'd say GWI) has a cramped UI.

You are right of course that some people like doing stuff differently. Some even believe that injecting Clorox into your veins is a good idea. And while people are free to do what they want (as long as it's not affecting others, that is), quite often these things are based on believe, prejudice and habits, and don't make much sense on a rational scale.

As to "making good use", despite this long thread I yet have to see *any* credible data demonstrating the claimed benefits of this method. On the contrary, because of this thread and people looking closer, we now have evidence that this non-standard method is, actually, severely limited, not just in support by scopes but also because it's need to having the scope halted for it to actually work.

I had the chance to quickly talk with some of our senior EEs about this during a telecon this morning, and let's just say that the feedback to this method hasn't been positive ('nuff said).


--- Quote ---Seems to me that just as cars all have different "personalities" that means they have to be driven slightly differently to get the best out of them, the same is true of scopes...
--- End quote ---

No, really not. The fundamental concept of *any* digital scope is that it allows you to capture (more or less, depending on the memory) long sequences and then lets you zoom in to the details. That's what they are designed for. It's really as straight forward as that.

And we should really stop with car analogies, because they are as stupid here as they are in most other situations they are used. Even more so when a lot of stuff regardings cars plays at emotional levels, not at technical ones.

Scopes aren't cars, they are test instrument to perform specific measurements based on scientific principles, working after an established understanding. Yes, there are differences in functionality and implementation, specs and cost, but they don't change the fact that they all conform to same fundamental concept. So because they aren't cars, you should not treat them as such.


--- Quote ---so the real meaning of "preparation" is to understand what your particular scope can do, and make the best use of it?
--- End quote ---

The meaning of preparation is to avoid jumping in blindsighted and then stumble at the first "ohh" moment when you realize you missed some crucial stuff (and yes, I am aware that this is exactly what many hobbyists do).

Testing doesn't mean just poking something with an instrument to see what's coming out. Testing properly means working methodologically, you have to spend some time thinking about what you have, what you want to achieve, what you ideally expect, what problems/issues you may encounter and how to address them, and then develop a test strategy which will give you the desired data in a reasonable amount of time and with reasonable effort. And then you go and execute your strategy. And if your strategy was sensible you get the data you need. If not, you re-strategize and execute again. Simples.
nctnico:

--- Quote from: Wuerstchenhund on May 11, 2020, 02:31:13 pm ---Testing doesn't mean just poking something with an instrument to see what's coming out. Testing properly means working methodologically, you have to spend some time thinking about what you have, what you want to achieve, what you ideally expect, what problems/issues you may encounter and how to address them, and then develop a test strategy which will give you the desired data in a reasonable amount of time and with reasonable effort. And then you go and execute your strategy.

--- End quote ---
And how does this tie in with the subject of this thread? You are still trying to convince people using half truths and straw man arguments an automatic gearbox should be used in manual mode only 'just because...'. Because of what?

So far your arguments seem to be:
- people who use recording beyond the screen are stupid and dumb
- an oscilloscope is not intended to do recording beyond the screen (I can show you a Tektronix manual which says otherwise but that wouldn't fit your Lecroy narrative)

All I'm seeing is someone who clearly isn't making his living using test equipment trying to tell real engineers how to do their job the right way as god intended. You just quoting randomly from the '10 Commandments of measuring' proves this.
tautech:

--- Quote from: EEVblog on May 10, 2020, 11:13:16 pm ---
--- Quote from: tautech on May 10, 2020, 11:03:20 pm ---The point is, zooming out is a crutch covering the far better methodology of zooming in.
--- End quote ---

Err, they aren't mutually exclusive!
Every scope works by zooming in, but it seems like the likes of Keysight have thought about it and implemented it slightly different to give you a potential added benefit if you so desire it.


--- Quote ---
--- Quote ---No, the problem is definitely that some seem to be stuck in the idea that you should always zoom in and use exact settings.
--- End quote ---

Alternatively, others are stuck on zoom out methodology which severely limits the capability of the tool in front of you.
--- End quote ---

He's just taking advantage of a feature of the scope that gives benefit to him in some cases. I don't see the problem with this and in publicising it.
I greatly doubt he uses it in every case, in fact that's not even possible.
--- End quote ---
Then why promote an arse backwards modus operandi when the tool set in most modern scopes is many times more capable ?


--- Quote from: EEVblog on May 10, 2020, 11:13:16 pm ---
--- Quote from: tautech on May 10, 2020, 11:03:20 pm ---While you are entitled to work with a scope in another 'round about' way those that you may train will have a shock if they go to work for others where zooming in is the universally accepted methodology.
--- End quote ---

Why be so hostile about learning a new way to get something done?
--- End quote ---
I'll offer you another memory trigger.
Certain members have used this arse backwards capture analysis MO to attack brands that don't support it and poisoned many threads over the years......if you need a further memory trigger, they have resulted in warnings and bans.


--- Quote ---Is it because you never knew about it before?
--- End quote ---

 ::)

--- Quote ---Is it because your beloved Siglent's don't have it?
--- End quote ---
Oh don't they ? Good, a brand that discourages arse backwards capture analysis.


But we need thank you Dave for pulling this discussion into its own thread where this weird capture analysis procedure gets some air and proper analysis of its own so it's clear that scopes, brands if you like and users each have their own toolset to undertake capture analysis albeit in some most unusual ways.

Now we have this thread I for one will be bookmarking it so further uncalled for poisonings of threads can be linked back here to let the reader decide what modus operandi are the universally accepted means of capture analysis and not some stabbing of buttons and twiddling of knobs but instead of a properly considered capture plan and a carefully set instrument.
Gandalf_Sr:
M: An argument isn't just contradiction.
O: Well! it CAN be!
M: No it can't!
M: An argument is a connected series of statements intended to establish a proposition.
O: No it isn't!
M: Yes it is! 'tisn't just contradiction.
O: Look, if I *argue* with you, I must take up a contrary position!
M: Yes but it isn't just saying 'no it isn't'.
O: Yes it is!
M: No it isn't!
O: Yes it is!
M: No it isn't!
O: Yes it is!
M: No it ISN'T! Argument is an intellectual process. Contradiction is just the automatic gainsaying of anything the other person says.
O: It is NOT!
M: It is!
O: Not at all!
M: It is!
Martin72:
 :-DD
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