Oscilloscope Zoom Out Quirk

[EEVblog]

[maginnovision]

I'd say the R&S has the best of both. Manual or auto mem depth and automatic history mode(it IS an option though). Although perhaps you'd say they're wasting memory as well which I'd agree with but luckily for me it's never been a limitation.

I noticed in the comments you said the segments wouldn't be time correlated(if sliding through time they'd show other segments), I THINK if you use list mode in history it'll tell where in time in relation to the final segment each segment was. The R&S do that.

[EEVblog]

I'd say the R&S has the best of both. Manual or auto mem depth and automatic history mode(it IS an option though). Although perhaps you'd say they're wasting memory as well which I'd agree with but luckily for me it's never been a limitation.

No I wouldn't say that if you can switch it off, it's done in auto mode.
But if you select a memory depth you should damn well get that memory depth.

[maginnovision]

Yea, that is a real difference. You get what you ask for. It's really odd setting a limit(and so few options too) for memory. May as well remove that entirely.

Just to clarify the history mode is a PAID option. You get whatever mem depth you ask for and however many segments(to a limit) it takes to fill available sample memory.

[EEVblog]

Yea, that is a real difference. You get what you ask for. It's really odd setting a limit(and so few options too) for memory. May as well remove that entirely.

Yes, on the Siglent you literally change the memory depth on the menu and the memory depth shown in the bottom sample window doesn't change. It's insane.

[EEVblog]

Just to clarify the history mode is a PAID option. You get whatever mem depth you ask for and however many segments(to a limit) it takes to fill available sample memory.

Not on the 2000X PLus it's not, no such option in the options screen.
https://int.siglent.com/products-ware/sds2000xp/

[maginnovision]

Just to clarify the history mode is a PAID option. You get whatever mem depth you ask for and however many segments(to a limit) it takes to fill available sample memory.

Not on the 2000X PLus it's not, no such option in the options screen.

Right, I'm talking about the RTB, RTM, RTA it's a paid option. I think it's standard on the 2kx+ but it'd better be since that kind of memory isn't as useful when you only actually get a small fraction of what's available during normal usage. Unless normally you need that kind of memory depth(100ms/div).

[TiN]

Tek DPO7k series don't zoom out, as the sample rate is locked together with sample depth, cannot set one without changing other

[jjoonathan]

Right, I'm talking about the RTB, RTM, RTA it's a paid option.

Yuck. It's standard on the RTE, RTO, and RTP, though, and those models also have a third timebase knob to control memory depth. I really love that third knob, it makes it super convenient to trade off vertical resolution / sample rate and time / RBW for FFTs.

[Elasia]

Yea, that is a real difference. You get what you ask for. It's really odd setting a limit(and so few options too) for memory. May as well remove that entirely.

Yes, on the Siglent you literally change the memory depth on the menu and the memory depth shown in the bottom sample window doesn't change. It's insane.

Dave.. your latest video just made me realize something..

It CAN zoomout! It's just not how you would think to do it...

To set it up, first set a timebase that will let you use the full 200M

UNDER the horizontal key press Zoom

THEN Zoom in to the actual display/timebase you want, you can zoom in just as a normal timebase change AND keep 200 Megapoints

when the event triggers you are interested in, just be on the bottom area and do the normal horizontal adjustment out OR use the top portion to drag it to one side or the other to the area you are interested in

The bottom area is the entire normal page but has been scaled down... i think this is why they make the menu bars also cause scaling of the main screen pixels

Try it out... and post another video

[maginnovision]

Right, I'm talking about the RTB, RTM, RTA it's a paid option.

Yuck. It's standard on the RTE, RTO, and RTP.

Doesn't bother me, I didn't pay for it anyway. I know you got yours for cheap but if you'd paid anywhere near msrp... You'd maybe not think it's so bad.

[Elasia]

And a screenshot so it doesnt look like im a nutter lol

[jjoonathan]

Right, I'm talking about the RTB, RTM, RTA it's a paid option.

Yuck. It's standard on the RTE, RTO, and RTP.

Doesn't bother me, I didn't pay for it anyway. I know you got yours for cheap but if you'd paid anywhere near msrp... You'd maybe not think it's so bad.

Very true.

[EEVblog]

Dave.. your latest video just made me realize something..
It CAN zoomout! It's just not how you would think to do it...
To set it up, first set a timebase that will let you use the full 200M
UNDER the horizontal key press Zoom
THEN Zoom in to the actual display/timebase you want, you can zoom in just as a normal timebase change AND keep 200 Megapoints
when the event triggers you are interested in, just be on the bottom area and do the normal horizontal adjustment out OR use the top portion to drag it to one side or the other to the area you are interested in
The bottom area is the entire normal page but has been scaled down... i think this is why they make the menu bars also cause scaling of the main screen pixels
Try it out... and post another video

Err, that's no different to just using a longer time base and pressing STOP or SINGLE, and then zooming in.
Using the dual screen zoom function whilst you do this makes no real difference.
This is NOT normal scope behavior and is not what is being discussed here.
The entire point of this is that you don't know you need the longer timebase until you do, so you couldn't have set it up like that to begin with.
Fact is on the Siglent the memory is not being set to the depth your specify, this is in inexcusable.

[Elasia]

No its trigger mode and auto as well

[Elasia]

Dave.. your latest video just made me realize something..
It CAN zoomout! It's just not how you would think to do it...
To set it up, first set a timebase that will let you use the full 200M
UNDER the horizontal key press Zoom
THEN Zoom in to the actual display/timebase you want, you can zoom in just as a normal timebase change AND keep 200 Megapoints
when the event triggers you are interested in, just be on the bottom area and do the normal horizontal adjustment out OR use the top portion to drag it to one side or the other to the area you are interested in
The bottom area is the entire normal page but has been scaled down... i think this is why they make the menu bars also cause scaling of the main screen pixels
Try it out... and post another video

Err, that's no different to just using a longer time base and pressing STOP or SINGLE, and then zooming in.
Using the dual screen zoom function whilst you do this makes no real difference.
This is NOT normal scope behavior and is not what is being discussed here.
The entire point of this is that you don't know you need the longer timebase until you do, so you couldn't have set it up like that to begin with.
Fact is on the Siglent the memory is not being set to the depth your specify, this is in inexcusable.

No its classic chinese out of the box thinking... you leave it like that in the first place and set your zoom in to where you want it.. works fine in all modes, stop, single, trigger, auto

[Elasia]

One other bit.. the refresh rate is a bit slow.. its not a killer for sure but it gets the job done

Those screenshots are the equivalent of 200 megapoints but on 500us trigger and a view finder on top.. granted the way you go about it is ass backwards but it still is functionally equivalent

[EEVblog]

granted the way you go about it is ass backwards but it still is functionally equivalent

It's so arse backward no one is going to use it for regular use. Again, you are missing the entire point of this.

[JPortici]

History (aka configured-by-default segmented memory) is still pretty nice for serial though.

Not really segmented mode but something like that (i've seen other scopes become completely unresponsive, minus the stop button, in order to maximise the sample rate.. somewhere else also called sequence)

But yeah, history mode is the best mode

[EEVblog]

Also the way LeCroy has always operated and the way Picoscopes have always operated.
Why do i have to keep telling people this?

That doesn't make it right.
Here is the thing. If you want to look at a short timebase signal then you'll set a short timebase, that's normal oscilloscope usage.
Even on a Siglent, Lecroy or Picoscope, you aren't going to go through to convoluted process of setting a slow timebase and then chosing the zoom mode and then setting the secondary timebase just for regular use.
The point is that when using the scope the normal way, you can't zoom out if you need to.

[SparkyFX]

A few years back I struggled to understand why scopes don't allow this full use of sample memory, as trigger processing should not affect it (effectively wasting the memory). Slower update rate might be a point, but if you consider that the use of more channels will limit the amount of data before and after triggering greatly because the memory organization will be affected, the usefulness of zooming out would vary a lot for each timebase - or cripple the sample memory per channel.

Therefore I rather like the segmented memory approach.

[nctnico]

A few years back I struggled to understand why scopes don't allow this full use of sample memory, as trigger processing should not affect it (effectively wasting the memory). Slower update rate might be a point, but if you consider that the use of more channels will limit the amount of data before and after triggering greatly because the memory organization will be affected, the usefulness of zooming out would vary a lot for each timebase - or cripple the sample memory per channel.

It doesn't matter at all. Sampling memory is per channel anyway and the memory is used as a circular buffer. There are no downsides.

[nctnico]

The question is "what does the scope do by default when it has extra memory beyond what's used by the configured acquisition." The three answers I've seen are "waste it," "extend the acquisition," and "hold on to past acquisitions." Wasting it is dumb, extending the acquisition is nice, but history is my favorite:

Maybe if I were doing a lot of serial decoding and running into partial packets my preference would flip.

The latter is the point: it greatly depends on the use case. Depending on what you are doing history mode (aka circular segmented recording) can be a huge waste as well because the memory can be put to better use as 1 long record for a measurement. In the grand scheme of things I have need for all modes (history, long memory, short memory, segmented recording) so when I buy an oscilloscope I make sure it can do all.

[EEVblog]

The latter is the point: it greatly depends on the use case. Depending on what you are doing history mode (aka circular segmented recording) can be a huge waste as well because the memory can be put to better use as 1 long record for a measurement. In the grand scheme of things I have need for all modes (history, long memory, short memory, segmented recording) so when I buy an oscilloscope I make sure it can do all.

And that's the thing. For a scope not to offer the full memory for a single capture even when deliberately selected (without using a convoluted dual timebase system) is just silly.
The user needs to be able to chose how that memory is used, and Siglent/Lecroy/Picoscope are seemingly the only ones crippled in this regard.

[nfmax]

A question for anyone with a scope that has the 'history' mode:

Does changing the settings between triggers, e.g. changing vertical or horizontal scale, or enabling an additional channel, clear the history buffer? If not, do such changes get reflected in the on-screen display of the settings, when reviewing history?