Hi I was playing around with uh, glitches in signals for another thing. uh, which I might see a future video on, but I Thought it'd be interesting to actually show you the glitch capture capabilities or pulse capture capabilities of modern Scopes and actually, uh, compare them and uh, see how useful they are. Oh, you might have seen one just pop up there. What? Oh, there there it is again.

What I've got is I'm just feeding in a pseudo random 1 megabit per second uh, signal a square wave Digital Signal into this and it's got a random glitch. both positive, uh, like going from the negative going up like this and also from the positive going down like this. um, at about a volt and a half or something like that. and uh, it's doing those random glitches about every 15 milliseconds and unfortunately, glitches are something that you might actually encounter.

uh, sooner or later if Murphy is going to bite you on the backside now. um, some. sometimes you'll just see like a glitch, like something like just pop up on the screen or briefly I think I saw it there Very briefly actually pop up you might think, oh, what is that? Well, there it is again. what is that? and how do I trigger off that? Well, of course, one of the easiest ways to do it.

of course. uh, with any scope, you don't need any fancy glitch capturing or pulse trigger uh capabilities if you just want to actually see if something's there. of course. uh, you can just use infinite persistence mode if you ever see like some weirdness happening on your screen not only turn your intensity uh up for your waveform, CU you'll see it uh, better but also turn on infinite uh persistence display so we can actually on this.

Roden Schwarz Mx4 Here we can go into settings. It'll be nice if they actually had this up the top or a button, but we can turn on infinite persistence here and let me actually reset that. Okay, I'll clear that after a couple of seconds. Boom.

We got our first one. Boom. We got another one. Uh boom.

there's one over here. Uh, come on. come on. Capture you bastard.

Come on. Oh, we haven't got one for a while yet. Hang on. they.

they'll come in bursts no pun intended Mir or weak. Anyway, you can see how that we're actually capturing these glitches there because uh, this just builds up. This display doesn't clear itself, so it builds up over time and you can get a picture of these actual Uh run pulses. Now, how often can we expect to actually see these things? Well, we can kind of sort of calculate this.

So what we know is our time base here is 1 microsc per division. Okay, we've got 10 divisions across the screen. That means we have an effective wind display capture window here of 10 micros wide. Now, as I said before, that, these pulses are appearing every 15 millisecond, so that's quite infrequent when you've only got a like a window like a sample window that's 10 microc wide.

So if you divide 15 milliseconds by 10 micros, you actually get 1,500 So if we reset our persistence here, we can only expect to actually capture this glitch like that every 1,500 captures of this entire display. Now of course, your scope's going to have a waveform updates per second. You know how many waveform updates per second, which changes based on the current time base and the current memory depth. And the good thing about the Radan Schwarz MXL is we can actually see this.

We can go into speed down here and we can actually measure and we can see the waveform update rate here. which is about, you know, let's call it 720 waveform updates. Uh, per second. So if our scope is capturing one of these 10 microc windows at a rate of 730 odd per second, well, we can expect it on average to capture one of those glitches about every 2 seconds or so.

And if we clear it, if we wait a couple of seconds, boom We We got one wait, another couple of seconds. Of course it's going to be more like it's going to be random because there's some blind time in there. Boom about every two seconds. So you can actually you know you can run the numbers on this.

If you know your Uh Acquisitions per second or your waveform update uh, speed in most Scopes you can actually get that from the trigger output. You can measure it on an external frequency counter. Uh, this is the only scope I've got that actually? uh, tells me. actually the scope actually tells me itself on screen how many waveform updates per second? But that's pretty cool, huh? We can actually estimate that.

So I've got a Dave CAD here to illustrate that. You can see that basically our pulses are happening every 15 milliseconds here. but basically because we're we're triggering wherever because there's you know, it's a very fast trigger uh rate. but uh, we've only capturing.

this. screen here represents only a 10 microc captal window as it's called and really your odds of of actually capturing one of those glitches which are essentially like just moving randomly even though they are a fixed 15 milliseconds apart. As far as the trigger system goes, they're just moving randomly across here, so the odds of finding one there are dependent upon your waveform update rate. and uh, how lucky you are.

Basically, and you know averages statistics. So that's why. if I clear that and we at you know 30 or waveform updates per second, we expect to capture one every couple of seconds. Cool, huh? But the next question is, how do we actually trigger of one of these Ah That's where it gets a bit more interesting and where your modern Scopes have features to actually do this.

And the other thing to remember is this has nothing to do with trigger level right? if I set my trigger level right in the middle there. Okay, we will still capture those because it's got nothing to do with uh triggering. It's just because because as I said, they're essentially just randomly wandering in the trigger uh sequence. so we don't even have to set our trigger level.

You can see that we're never triggering off actually one of these things. so trigger has nothing to do with it. Essentially in this particular case, although your mileage may vary so modern Scopes like this Roden Schwarz Mx4, they will actually have Glitch capture capability. So let's actually turn off.

Okay, so we know our glitches happening there. Okay, we've captured it with our consistence view here. so we know the you know we can go in there with our curses or just eyeball measure. Uh, that.

So we know the pulse width that is happening here. We know the signal level roughly so you know one division up would be a nice trigger level for that. one division down would be a nice trigger level. uh for that for example.

So if we know the pulse width and we know the trigger level, we can use glitch or pulse, uh, capture. It depends on the manufacturer. they might call it something. uh, different.

So let's turn off the uh infinite persistence display there and we're back to here. and as you can see like we will very rarely. Oh whoa, we got one over there. So if we want to trigger off that, we go up to trigger here and then we can choose the trigger type.

And this actually has glitch capture here. Now of course you can do uh, run and width and they're different, uh, styles of trigger, but glitch is essentially a pulse uh, width type thing. Now let's actually set this up and you can see where actually there's something in the middle here as well. So there's something going on.

We've already triggering off something there, right? So what we want to do is actually set our trigger level here, which you can like set here or just use your regular trigger level. Let's try and capture on one of those bottom ones. So about a division up. Uh, we can either choose shorter or longer.

we want the shorter option because it's a short uh pulse and then we can set the pulse width right. So we want to set that pulse width just above where we think it is there. Okay, let's let's just say 70 nond or thereabouts. and we're triggering off that thing perfectly.

Okay, Oh I Forgot to mention, we're actually in normal uh, trigger mode here. Okay, and we can actually do that same thing for the positive glitch up here. Okay, we can set our trigger level up to here and boom, we're getting that, but we probably want to set that. to negative going now.

And bingo, we are now triggering on that actual glitch there. Neat huh? Now, because we're actually triggering off this glitch here. We're not just randomly wandering through this window back and forth like we were before. Essentially because we're triggering on.

we expect more than a couple of times waveform updates per second and you can see we're actually getting that we can see here. it's actually 30, 30, 35, maybe waveform updates per second. So now we're actually capturing that cuz once we've captured it, it'll rearm and then we'll capture it again. We will capture that more frequently than when it was just randomly wandering through here.

So we're getting a That's why we're getting a faster waveform updates per second there. Now, this is actually glitch capture. Because it's we're essentially doing What that means is we're doing pulse capture. That's why on a lot of Scopes it'll be called pulse capture because we're specifying the actual uh, you know, the pulse width ranging here either shorter, like lower, or more than a certain uh value.

But uh, because it's based on Signal level as well, we can actually use Uh run capture as well to do this. So This Basically, instead of working on a horizontal, it works on a vertical basis. Um, I've been calling this a glitch, but what this is is actually in this particular scenario is actually a classic run pulse. So what a run pulse is is that you can see that the normal signal level like a you know it's a TTL type signal level 5 Vols 3.3 or whatever right digital signal.

But a run pulse means that it only goes up a certain amount of way and doesn't reach a certain. It doesn't reach the upper digital threshold because if you know about digital logic, they have upper and lower thresholds before they're actually recognized as a logic one or a logic zero. So a run pulse actually doesn't go all the way up to the second threshold. so you can actually do.

And modern Scopes actually have also uh, run triggering so that is one of the options there so we can choose run triggering like this. And then we've got an upper level like this. So we set our upper level like that so it might be up here. uh, for example, and a lower level.

So it was right down at the lower level down there. So it transitions through one level, but it doesn't transition through the other level so you can see those two levels. It transitions through one but doesn't go through the other and that's the definition of a run pulse. And then we can do uh, range.

Here we can just longer, shorter within outside. Uh, or we can do this automatic find level. Let's see if we can do this. Okay, Boom there it is.

It automatically found it very cool and you'll see that if I choose the upper limit there and I go below the Run value right in there. It's not going to actually capture that, it's stopped capturing. it's actually Frozen. So if I actually, uh, clear that there, you'll find that we won't actually capture that.

It's only when we go above that level boom that we start to capture that. So, but even run or glitch capture in this case works. and I know you're thinking Dave I can capture this using the fancy pancy history mode of this Mx4 scope. Well, yeah, not really.

it's going to be based on luck. um, and that sliding window and the odds of actually capturing it like we saw before. So if I stop this. okay, yeah, we can go into history mode and over here.

We've got 16,000 Acquisitions here and you can go through them one by one by one by one one until you try and find a glitch in there. Of all these waveform captures that it got, but you're going to be waiting there a long time. You're going to look through it like statistically, we've only looked through like 300 so far. we're going to have to look through a lot more than that before.

On average, we're going to actually find one. We're going through pretty quick, so you could easily visually miss one. My Mark 1 eyeball might not actually see it, but you know you might eventually get lucky and see one if you if you're patient enough. But based on the math we did before, you can only expect a capture at every like 1,500 waveform captures on average, so you could be there for a while.

Of course you can set it to auto scroll through of course at a certain speed and you can just try not to. Blink Good luck, but those two methods aren't the only ones you can use on this uh Roden Schwarz scope. It's got another very cool mode trigger mode that I'll show you here and you can see that we are actually capturing, but it's a slower update rate there. There you go.

But what we're actually using this time is what's called interval uh trigger in here. so it's one of the very comprehensive uh, you know, types of different Uh triggering systems. Not every scope will actually have this and we've got interval trigger. We can set it up shorter here or we can set it longer within or outside so it's extremely powerful and we've set the Uh trigger level to there right and then I've got the inter width set to 80 nond there.

and of course it's going to trigger on anything less than 80. NS Very. It's another way to actually capture it. Check this out! This is very cool.

It's got this find level here so it's got this automatic level. Watch this find level and boom look at that we've captured on This middle one here which is yet another glitch in here. Like this: messages booting. oh touchy feely screen so it's automatically found this glitch in here.

This is absolutely fantastic. So as far as I know, um, this is the only scope I've got that will actually do that automatic uh detection, uh capability and stuff like that that. it's very cool. So that's very I think that's quite specific to this scope.

If you know of another one that can actually do that, leave it in the comments down below. but I just think that's fantastic. Okay, let's try another excellent modern uh oscilloscope here. The signant DS 23 54x I don't know there who I was looking at it before and it was taking a while, but yeah, it's I think it's a slower waveform update rate might help if I turn my intensity up a bit we might see it a bit better.

but yeah, not quite. Oh yeah, yeah, got one. We got one. So if we go into our uh trigger mode here, we get we The Edge type but we got all these different uh types as well.

You notice that it doesn't have uh, they don't call it glitch like that, but we can use pulse triggering here. It's got run triggering and drop out and all sorts of things, but we should be able to do the same thing with pulse triggering and Boom! we've got it here Now this one. it does it like, explains it a little bit. uh, differently here.

but we can choose the different Uh limit ranges. here. we can choose less than or equal to a value. We can choose greater than or equal to a value.

We can choose within two particular values or we can choose outside uh, two particular values here. But if we choose inside a particular value, so it's within 79 nond and 2 NS Boom there it is there. No worries. And we can also use the Run uh trigger thing here.

Once again, we can choose the different Uh Styles there and we've got uh, the positive Edge but I'm only at 28 nond at the moment. so if it TR if it transitions through this signal level here and not this signal level here, we should be able to pick it up. So if I increase that. but that's also dependent upon the time as well.

Oh there it is. So once we got greater than the pulse width of that little run pulse there, which we can actually measure, use this as a tool to measure it without using our cursors. We see once we hit about 55, once this baby hits 55 M hour, you're going to see some serious run pulses. And just to show you that you don't need a big, fancy, expensive oscilloscope to do it.

Bottom of the range: Riy Gold Dho 800 here. No worries whatsoever, there is our glitch. We're using pulse triggering. It's got all the different fancy types we got.

we're using pulse triggering at the moment, but it's got run, it's got timeout, it's got inedge, and it's got duration and more things than you can poke a stick at. No worries. And if you choose pulse, you've got the different types here. I've got it set to 80 NCS Here you just set the level Bobs your uncles so we can set our two levels for run there and our lower level is around about there.

No worries. And bingo there's your run pulse and of course you can single shot capture that every single time so you don't need need an expensive scope to get these sorts of advanced trigger. Cape Mes, it's they're now available on the absolute bottom of the range. sub $400 Scopes Brilliant.

You just know how need to know how to use them and again to find the Run pulse in the first place. Doesn't matter if you have a fast, updating scope or not, and well, this one's actually pretty quick. Um, you can set your infinite uh, persistence here and then we can clear that and then they'll pop up. No worries, Come on there we go.

Not a problem. So you know that something's there and then once you know something's there, you can then set up the requirements to trigger off it. And the classic key site 3000 You know this bad boy is going to do it and we set it to pulse trigger here. Once again, we got positive or negative.

We've got the Uh less than greater than or Uh window so you'll see that works just fine. and if I continually single shot capture that, you'll notice that really, there is no synchronization between this uh uh run pulse glitch and the actual edges of the waveform itself. So that's why it's kind of like free running as you'd call it. There you go s it practically corresponded with you might not see it at all cuz it might perfectly correspond with a like rising or falling Edge there, so you may not see it.

but that's what happens when it's not actually synchronized with the actual main waveform itself and that might actually technically make it hard to do uh trigger off. And likewise, we can do a run triggering here. We've got all the Usual Suspects and we can select our high and low signal levels. and also we've got our qualifiers as well.

They actually call them qualifier, so a lot of uh Scopes will call these things and the selections and setup of them. You know something. They'll use some different terminology, but they're essentially all doing all the same thing. And of course, we can't leave the tetronics Fanboys out.

So yeah, we've got pulsewidth. We've got R We've got all of them. So there you go. There's the oh there, there's the pulse width.

No problems whatsoever, ever. But wait, there's one more. There's one more type of triggering that might in this case be able to get it and that oh, you just saw it. Update: There is zone triggering.

Now my uh key site has this: my Roden Schwarz has a Zone button. You can see it up the top there, but if I press it, it does nothing cuz it's not functional yet. Come on, What are you doing? Um, Anyway, yeah, you can actually set up. Okay, so you can see I've actually set a I've drawn on the screen a Zone there and it's you see, it's actually captured it twice.

But the problem with zone triggering is that it's screen based so you don't know. Oh, there we go. did we get another one? You don't know where it's going to pop up on the window so to speak, because remember, it's asynchronous. So what zone triggering can do? If you've got a stable trigger signal like this, then if we can, we can actually set a Zone in there where if anything goes like within that window, then it's going to uh, trigger on it so we can actually turn that on and we can draw I've I've done it there.

I've drawn a small window there which is outside of where it would normally trigger and it's now. It's just going to sit there and wait. So and wait and wait and wait. and if you get lucky.

but once again, we we got one. There you go. We got one that actually happened because this actually shifted the trigger signal here. Um, and the main signal was here.

but it it doesn't matter as long as it went through that window there. So either if oh, we got one, got another one. So if the glitch actually either the glitch is in there or the actual Uh signal is in there, then it you can actually capture on that and we've actually got the trigger level. We can actually turn it up so that it'll never trigger on the glitch and we can just sit there waiting and waiting to see if the glitch actually catches actually comes up in there.

But you know you could be waiting a while. So technically it works, but it's not really the right tool for the job one and I can actually draw a little Zone around that. Okay, and then I can say it must intersect with that. but when I actually run it, you might think that it's triggering in there, but it's not.

It's actually doing that because I'm still on run trigger mode. So I don't get fooled by that. If I turn that back to regular Edge triggering, we're back to the point where it's not going to actually do that if we do single shot capture. Okay, single shot capture.

we're not going to actually the pulse. It's just going to be like random. It intersects that zone and that's not really what you want. so don't use Zone trigger anyway.

I Hope you have enjoyed that. look at uh, some more advanced uh trigger types in modern Scopes but even you don't have to get an expensive one even the lower end ones have these these days. and I hope you learned something from that if you did. Please give it a big thumbs up if you like these sorts of like more advanced um, test equipment tutorials please.

Yeah, thumbs it up. Leave it in the comments down below and maybe we can do some more. And as always you can comment on the EV blog Forum or down below and I do have a new store as well EV blog. store link down below where you can help keep the blog Alive by buying some stuff.

Catch you next time.