Products > Test Equipment
Oscilloscope Zoom Out Quirk
kcbrown:
--- Quote from: 2N3055 on October 23, 2022, 07:52:11 pm ---
--- Quote from: kcbrown on October 23, 2022, 07:18:04 pm ---...
I will say this: for single capture mode, it really should use all the available memory always. This is because the history buys you nothing, since each time you press the "single" button it'll clear the history, so the scope may as well use all the memory for the one capture you're performing. This is the one exception that Siglent should have made to the "what you see is all you get" behavior from the start. Either that, or it should remember prior captures as long as the capture parameters (timebase, trigger settings, etc.) remain the same.
--- End quote ---
There is a common scenario where history mode makes perfect sense even in single mode.
And that is when you are experimenting, you tweak something in your DUT (analog or digital) and take single capture, tweak few minutes, capture that ... Now you have 20 captures over 2 hours. You go in history mode and overlay them, measure, decode. compare..
You can save them for documentation if you want then.
--- End quote ---
Except that on the Siglent, you can't do this. I wish you could.
Whenever you hit the "single" button, it clears the history.
Did they change that behavior in the models above the 2000X+? Because you certainly can't get multiple history entries via "single" on the 2000X+.
2N3055:
--- Quote from: kcbrown on October 23, 2022, 09:42:34 pm ---
--- Quote from: 2N3055 on October 23, 2022, 07:52:11 pm ---
--- Quote from: kcbrown on October 23, 2022, 07:18:04 pm ---...
I will say this: for single capture mode, it really should use all the available memory always. This is because the history buys you nothing, since each time you press the "single" button it'll clear the history, so the scope may as well use all the memory for the one capture you're performing. This is the one exception that Siglent should have made to the "what you see is all you get" behavior from the start. Either that, or it should remember prior captures as long as the capture parameters (timebase, trigger settings, etc.) remain the same.
--- End quote ---
There is a common scenario where history mode makes perfect sense even in single mode.
And that is when you are experimenting, you tweak something in your DUT (analog or digital) and take single capture, tweak few minutes, capture that ... Now you have 20 captures over 2 hours. You go in history mode and overlay them, measure, decode. compare..
You can save them for documentation if you want then.
--- End quote ---
Except that on the Siglent, you can't do this. I wish you could.
Whenever you hit the "single" button, it clears the history.
Did they change that behavior in the models above the 2000X+? Because you certainly can't get multiple history entries via "single" on the 2000X+.
--- End quote ---
HUh.. let me check this..
No you're right, it does not...
I must have confused it with something that was discussed..
Sorry!
Martin72:
Hmm....smells like a feature adding in future firmwares...
2N3055:
--- Quote from: Martin72 on October 23, 2022, 09:49:57 pm ---Hmm....smells like a feature adding in future firmwares...
--- End quote ---
Not that I know of, really I remember a lengthy discussion about it and probably something left in my head...
kcbrown:
--- Quote from: nctnico on October 23, 2022, 07:47:43 pm ---
--- Quote from: kcbrown on October 23, 2022, 07:18:04 pm ---OK, but you have to set the timebase to something. How do you set it on your scope so as to get the maximum capture depth while also retaining the sample rate you want?
--- End quote ---
You are overthinking it. Zen master says: 'Try not to find problems that aren't there'.
--- End quote ---
Except I'm not overthinking it. It's simply a question of how to get the capture characteristics to be what you want them to be. Since there are situations in which you don't care about what the timebase setting is, it follows that you can then use the timebase to get the capture size you want in those situations. Point being that those situations, which you explicitly called out, are precisely the ones where you have the fewest valid objections to Siglent's "what you see is all you get" approach.
Where the scope behavior you advocate for becomes truly useful is when you do care about the timebase setting and you want to use all of the available (or configured) memory for the capture.
--- Quote ---All DSOs except for the ones from Lecroy and some older Siglent models, allow at least to force full memory.
--- End quote ---
You can force full memory in all of the Siglent scopes. It's just a question of how to go about it. For the "what you see is all you get" scopes, you force that via the appropriate timebase setting.
It's a tradeoff. The downside of the "what you see is all you get" approach is that you don't get to use all of the configured memory while having a smaller timebase. The upside of it is that (save for the maximum capture buffer size, which is separately configured) you fully control the entire capture configuration with a single setting (the timebase) and you always know exactly what you're going to get without having to reference anything other than the timebase settings.
Ideally, you want to be able to choose which approach to take. Fortunately, Siglent has seen the light on that and now makes that possible.
One approach that no scope manufacturer I know of implements would be to allow the user to specify the maximum capture length as a multiple of the time represented by the screen as defined by the timebase setting So, for instance, you might set it to 10x, and thus you'd always capture 10 times the amount of time shown on the screen. Such an approach would retain the primary advantage of "what you see is all you get", namely that it would make it possible for you to always know exactly what you're going to get, and it would allow you to always zoom out by the configured amount. The remaining memory (if available) would then be used to store prior captures in the way Siglent already does.
--- Quote ---And several offer an automatic mode.
--- End quote ---
It's not clear to me what specific advantages that would have, most especially if the particulars of "automatic mode" are manufacturer-specific, as I'd expect them to be.
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