EEVblog #1312 - Siglent Oscilloscopes CRIPPLING History Mode!

[tautech]

Snoopy, this is from a SDS5000X and the SDS2000X Plus should perform exactly the same albeit with a tiny bit less memory depth. (250 vs 200 Mpts)
Setting used was 62.5 Mpts, being 1/2 of the full available mem depth as we are using 3 channels for which the max is 125 Mpts/ch.

Settings returned 433 History frames that we can step through one at a time or play them in forward or reverse order.
No particular order other than what the Frame # signifies.

So you are triggering on start of frame or when chip select asserted ?

Clock falling edge, visible in the Trigger setting box.   

What happens if the packet size is different for each frame ?

Don't think they are from this STB3.

Will the history automatically record packets of varying length ??

No reason why it shouldn't.

I can see this method saving a lot of record memory that is wasted dead time between packets Interesting if it works like this

I believe it does and I'll come back with a screenshot soon....not entirely sure.

[tautech]

This shot with trigger centered and traces moved upwards is the same source and settings as before but with Cursors added to measure the inactivity time between packets. Live running capture whereas previous shots were in History from a Stop capture. List ON.


So yes this below shot posted before indicates a pile of trace inactivity time removed but that will be related to timebase settings with triggering dictating the # of frames captured and no doubt History playback setting also.

[TK]

@snoopy: I don’t think history mode can capture different timebase intervals. It will be fixed and if tou have variable frame length I am not sure how any scope will do such capture. I will test later on a KS and GDS1054B with segmented memory with variable SPI frame size

[nctnico]

@snoopy: I don’t think history mode can capture different timebase intervals. It will be fixed and if tou have variable frame length I am not sure how any scope will do such capture. I will test later on a KS and GDS1054B with segmented memory with variable SPI frame size

History mode / segmented recording will always work with fixed buffer sizes. AFAIK the only oscilloscopes which can show decoded packets from all segments in one list view are from Keysight. It is a rather unique feature which can be very useful though.

[2N3055]

@snoopy: I don’t think history mode can capture different timebase intervals. It will be fixed and if tou have variable frame length I am not sure how any scope will do such capture. I will test later on a KS and GDS1054B with segmented memory with variable SPI frame size

History mode / segmented recording will always work with fixed buffer sizes. AFAIK the only oscilloscopes which can show decoded packets from all segments in one list view are from Keysight. It is a rather unique feature which can be very useful though.

I agree, and that is my problem with Siglent (and RTM3000 from R&S) SDS2000X+ and SDS5000X. That, and search on protocols.

Just wanted to add (I know I'm boring everybody with it, sorry ) but Picoscope also decodes current buffer or all segments or history buffers. It also can use DeepMeasure over both current or all history buffers.

[TK]

I ran some SPI decoding tests some time ago on KS and Siglent and posted here: https://www.eevblog.com/forum/testgear/impressive-keysight-1000x-series-(edux1002g-modded)-spi-triggering-rate/msg2413935/#msg2413935

It is interesting how KS screen display and decoding buffer seem to go through different paths inside the scope.  Even when the waveform is very distorted, it can decode correctly

[2N3055]

I ran some SPI decoding tests some time ago on KS and Siglent and posted here: https://www.eevblog.com/forum/testgear/impressive-keysight-1000x-series-(edux1002g-modded)-spi-triggering-rate/msg2413935/#msg2413935

It is interesting how KS screen display and decoding buffer seem to go through different paths inside the scope.  Even when the waveform is very distorted, it can decode correctly

It doesn't seem, it literally does have dual paths to A/D converter and to digital edge detector. And, you are correct, it is sometimes simply weird how it decodes nicely when signal is completely scrambled on screen...

[Triodos]

Hi, I'm new here, and few days ago I bought SDS1104X-e with SDG1032X.
And I was really happy until today I discovered that thread ...

I was wondering why I cannot put whole 14 Mpts all the time and now i see why.
I work mostly in analog domain, and zooming out before single shot is not a big deal.
Playing with horizontal know it is easy to to find a point where whole memory is used for one single shot.

But I agree that it would be nice to let me choose the way the memory is used and be able just to zoom out after single shot if I want it.

[tautech]

Hi, I'm new here, and few days ago I bought SDS1104X-e with SDG1032X.
And I was really happy until today I discovered that thread ...

I was wondering why I cannot put whole 14 Mpts all the time and now i see why.
I work mostly in analog domain, and zooming out before single shot is not a big deal.
Playing with horizontal know it is easy to to find a point where whole memory is used for one single shot.

But I agree that it would be nice to let me choose the way the memory is used and be able just to zoom out after single shot if I want it.

Welcome to the forum.

Key is understanding capture strategies and embracing the methodology to obtain the result you seek.
Zoom out, capture, then zoom in and navigate is not hard to get a handle on. 

Understand interleaving also helps so the channels selected use all the memory available. 1+3, 1+4, 2+3, 2+4 utilize the available memory to best effect.

[Triodos]

Hi, I'm new here, and few days ago I bought SDS1104X-e with SDG1032X.
And I was really happy until today I discovered that thread ...

I was wondering why I cannot put whole 14 Mpts all the time and now i see why.
I work mostly in analog domain, and zooming out before single shot is not a big deal.
Playing with horizontal know it is easy to to find a point where whole memory is used for one single shot.

But I agree that it would be nice to let me choose the way the memory is used and be able just to zoom out after single shot if I want it.

Welcome to the forum.

Key is understanding capture strategies and embracing the methodology to obtain the result you seek.
Zoom out, capture, then zoom in and navigate is not hard to get a handle on. 

Understand interleaving also helps so the channels selected use all the memory available. 1+3, 1+4, 2+3, 2+4 utilize the available memory to best effect.

Oh, that was what I forgot, that there are two ADCs for 4 channels 1-2 and 3-4. Thanks for a tip

[tom.holzwurm]

Sorry for being late, but I hadn't seen this discussion and the video just now:
My good old Tek 754D hasn't of course such much memory but a nice zoom function, which I use very often, You can see the origial signal and can zoom in using a sliding magnifying window.
I still do not understand, whats the difference from the Siglents nasty? behaviour to that of my scope ?
Thanks for enlightening me,
Regards
Tom
PS: I'm currently looking for a replacement, that's why I'm asking.

[TK]

All scopes can zoom in, but not all can zoom out from a fresh capture. In the siglent, when you zoom out after capture you see no additional data because it just used enough sample memory to what is in the display, even when you indicate you want to use more

[tautech]

All scopes can zoom in, but not all can zoom out from a fresh capture. In the siglent, when you zoom out after capture you see no additional data because it just used enough sample memory to what is in the display, even when you indicate you want to use more

RTFM on mem depth management.
In Zoom mode it's a totally different scenario.

Embrace how Pico, LeCroy and Siglent manage captures and there are no disadvantages,

[nctnico]

Sorry for being late, but I hadn't seen this discussion and the video just now:
My good old Tek 754D hasn't of course such much memory but a nice zoom function, which I use very often, You can see the origial signal and can zoom in using a sliding magnifying window.
I still do not understand, whats the difference from the Siglents nasty? behaviour to that of my scope ?

It depends on what you are doing but for some measurements you don't want to have the zoom windows around in order to save space (to have measurements or the waveform on screen). Or you just didn't enable it. Or it turns out you forgot to reset the screen position before doing a new measurement. Being able to scroll left / right / zoom out saves you time. Especially if doing the actual measurement takes a long time. At that point not being able to zoom out would get seriously in the way of being efficient. That is it in a nutshell; there is much more to it. AFAIK your TDS754D should also be able to zoom out; just disable 'fit to screen' and you can scroll left/right just like every other DSO out there (except for Lecroy and Siglent). However it seems Siglent is working on a fix but no ETA yet.

[tom.holzwurm]

 Not to be misunderstood: I heavily use the zoom function on my Tek, I was wondering if the Siglent is able to provide the same option, which it doesn't according to this article.

[0xdeadbeef]

This is not about zoom, it's about some people expecting a scope to capture data outside the screen area defined by the operator since obviously the operator didn't really know what he wanted to look at.

[2N3055]

Not to be misunderstood: I heavily use the zoom function on my Tek, I was wondering if the Siglent is able to provide the same option, which it doesn't according to this article.

Complete topic is BS. It has very well implemented zoom. It has also well implemented history mode that will keep thousands of previous triggered captures without performance impact. Sort of transparent segmented mode always running in the background.

[nctnico]

Not to be misunderstood: I heavily use the zoom function on my Tek, I was wondering if the Siglent is able to provide the same option, which it doesn't according to this article.

Complete topic is BS.

It is not. An oscilloscope which works like Siglent is useless for many of my measurements because it would seriously slow me down. You just don't see the how and why. That is fine. Since you're not a Siglent sales agent I don't get why you are calling this BS. It doesn't make sense. Many people have pointed out that capturing beyond the screen is useful to them. Who are you to tell them different?

[2N3055]

Not to be misunderstood: I heavily use the zoom function on my Tek, I was wondering if the Siglent is able to provide the same option, which it doesn't according to this article.

Complete topic is BS.

It is not. An oscilloscope which works like Siglent is useless for many of my measurements because it would seriously slow me down. You just don't see the how and why. That is fine. Since you're not a Siglent sales agent I don't get why you are calling this BS. It doesn't make sense. Many people have pointed out that capturing beyond the screen is useful to them. Who are you to tell them different?

I agreed, after lengthy discussion, that it is not useless. But it is obscure, and NOBODY even understood what are you talking about before you took some lengthy explaining how you do it. 
So yes using word "crippling" for something nobody knew about (except you) until then is BS. Utter BS. And so is proclaiming that History mode is useless (which is something LeCroy users use all the time for many years) and that it is a mistake doing History mode instead very rarely (or never) used arcane feature.
I have History mode on Picoscope and use it all the time...

[nctnico]

Not to be misunderstood: I heavily use the zoom function on my Tek, I was wondering if the Siglent is able to provide the same option, which it doesn't according to this article.

Complete topic is BS.

It is not. An oscilloscope which works like Siglent is useless for many of my measurements because it would seriously slow me down. You just don't see the how and why. That is fine. Since you're not a Siglent sales agent I don't get why you are calling this BS. It doesn't make sense. Many people have pointed out that capturing beyond the screen is useful to them. Who are you to tell them different?

I agreed, after lengthy discussion, that it is not useless. But it is obscure, and NOBODY even understood what are you talking about before you took some lengthy explaining how you do it. 

So it is not BS then. 

And that nobody understood what I was on about isn't true. If you look at the forum threads and Youtube comments it turns out lots of people take the 'capture beyond the screen' for granted. It is like being able to ride a bicycle. But now try to explain how to ride a bicycle exactly.

[2N3055]

Not to be misunderstood: I heavily use the zoom function on my Tek, I was wondering if the Siglent is able to provide the same option, which it doesn't according to this article.

Complete topic is BS.

It is not. An oscilloscope which works like Siglent is useless for many of my measurements because it would seriously slow me down. You just don't see the how and why. That is fine. Since you're not a Siglent sales agent I don't get why you are calling this BS. It doesn't make sense. Many people have pointed out that capturing beyond the screen is useful to them. Who are you to tell them different?

I agreed, after lengthy discussion, that it is not useless. But it is obscure, and NOBODY even understood what are you talking about before you took some lengthy explaining how you do it. 

So it is not BS then. 

That is very example how you try to provoke people's reaction by outright lying what I said by simply ignoring rest of my sentence..
Good work! 

[PickNickOnPluto]

Being new to digital scopes (I've used a Bitscope for years, but it's not in the same league), this discussion has been enlightening. But it shows that even experienced users don't seem to understand a lot of the fine points. It would be a great help, I think, if someone could write a really detailed guide or manual that describes, firstly, what each of the menu options really does, and secondly, how it can be used for specific measurement problems, and how it interacts with other options. I find again and again that I don't understand exactly what an option is doing, and I don't know where to get an answer. I was mystified by the fact that my SDS2202x-e seems to hang when you start a long capture, doesn't react to most button presses. If somewhere I were told that this was necessary to get maximum capture rate, I wouldn't have been so annoyed, but I'm still not sure it's not a bug that should be reported. What does "Acq Mode Slow" in triggering "Type Edge" do? Is it equivalent to a long holdoff time? Why is there no holdoff time for "Type Slope"? I don't see why we should have to speculate about these things -- it's as if we were dealing with some sort of exotic biological creature.

[SMB784]

Being new to digital scopes (I've used a Bitscope for years, but it's not in the same league), this discussion has been enlightening. But it shows that even experienced users don't seem to understand a lot of the fine points. It would be a great help, I think, if someone could write a really detailed guide or manual that describes, firstly, what each of the menu options really does, and secondly, how it can be used for specific measurement problems, and how it interacts with other options. I find again and again that I don't understand exactly what an option is doing, and I don't know where to get an answer. I was mystified by the fact that my SDS2202x-e seems to hang when you start a long capture, doesn't react to most button presses. If somewhere I were told that this was necessary to get maximum capture rate, I wouldn't have been so annoyed, but I'm still not sure it's not a bug that should be reported. What does "Acq Mode Slow" in triggering "Type Edge" do? Is it equivalent to a long holdoff time? Why is there no holdoff time for "Type Slope"? I don't see why we should have to speculate about these things -- it's as if we were dealing with some sort of exotic biological creature.

What you are describing is called the user manual for the scope, and the SDS2202x-e has one that you should read.  These things are all described there.  You can find the link to the manual here