Hi, it's time for another oscilloscope tutorial and I've actually done I Hope you don't know a whole bunch of oscilloscope tutorials. I've got a YouTube playlist which I'll link in at the end and down below. It's currently got about 30 videos on it for various oscilloscope tutorials. Anyway, this one today is a little bit more obscure and not available on all scopes, but it could be really valuable if you're looking at two correlated signals that are quite far apart.

so let's take a look at that. We're using our Keysight 3000 X-series because this happens to have the feature that we're looking for that's going to enable this and this is really interesting. So what? I've got here? Channel A, Channel B and I've just got two signals here. They're actually like little bursts of square wave here like this.

and it's the same on Channel 2 down here. But of course, to go in and see Channel 2, that's our problem. How do we go in and look at Channel 2? Oh, it's easy. Dave Go in there, trigger, select your source going there, and we're now triggering off Channel 2.

Thank you very much and we can go in there and have a look at Channel 2. Okay, that's great, but how can we look at both of them at the same time with any sort of detail? Ha I Know is saying Dave That's easy too. All you got to do is single-shot capture that put it at a reasonable time base and then zoom in. Ah, look at that.

Depending on our memory depth, we've come a got so there's not much detail in there is there that's pretty awful. And then of course we can scroll over to channel one over here. do I call it channel ie. before Anyway, old school.

Okay, so we can view independent ones that wouldn't go in there with our curses and we can measure things. And we can you know, count the number of cycles a'queen We can analyze each one independently, but it's kind of like a multi-step process. We actually run this thing. How do we actually get both of these signals on the screen at the same time correlated together? Hmm.

You might think it's impossible, but it's not. So pause this video and try to figure out you can get both of these zoomed in like that so one above the other so that we can then compare them. Because often you'll have two correlated signals like this one might affect the other, but they're actually spaced a long way apart and you want to see their response. You know one compared to the other.

You want to overlay them. How can you do it? So this seemingly impossible task is actually very easy for an advanced scope that has this feature. Let's go into trigger here and the different types over here and you might be like modern scopes just have a ton of different types of trigger. You know, runt pulses in edge bursts, rise and fall, and all that sort of jazz.

But what we want is this rather obscure one down here called or so. let's actually select that and if you have a look down here, we now get an option to set up. or it's got all the channels about the four analog channels and the four digital channels like this. So what this is gonna allow us to do is exactly as the name implies.

it's an all trigger, just like a digital logic function or so it can trigger on Channel one or Channel two. So at the moment we've only got trigger one enabled here and we can select the slope we want rise in falling, or either or don't care for channel one. and then we'll select channel two and we can select rising for channel two as well. And bingo if we go in there, look at that magic.

Now this is actually quite amazing. We've actually got both signals now what looks like their time correlated, but there's not. There's actually a big difference in time between them as you saw before, but as well as you can still see if we kind of do that and if we single-shot capture that, only one of them will ever be there at any one time. but it's just kind of essentially randomly triggering off either channel one or Channel two.

Hence, the trigger type Fung called all isn't that fantastic and you can tell that they're sort of swapping between them because of the thick look at the line down the bottom. Well, no I just bloody touchscreens the the line down the bottom so you can tell that it's actually overlaying that on the screen multiple times. But yeah, that's beautiful. So now we can actually get in there and see that our Channel 2 signal is actually half the length of the one at the top.

Then we can just go in there and analyze those. Isn't that cool? Love it. But you got to remember you could actually come a Gansa with this because if you're just like and called your colleague over a bill, come over here. check this out and look at these signals here.

They would with if they didn't know if you weren't in the trigger screen like that. how would you tell you would think that their time correlated? wouldn't you? you would think oh look, they're both starting at the same time. Yeah, obviously the only thing that's telling you is that little trigger annunciator up there, the little green one that's just showing the or symbol and well, unless you know what all triggering is actually doing, there's nothing else on here to indicate that these are not proper time correlated signals. So the only indication you're going to get is if you hit that stop button and you only get the one or you hit the single-shot button, There you go.

Aha, those two aren't really correlated. it's a trap, so we're effectively viewing both in real time. Although the Scopes actually sort of like Oulton and the olden school alternate trigger on analog scopes, it jump in between them. but it's doing it so fast that they're both on there at the same time.

So this all a trigger type is effectively replacing the alternate trigger function that they used to have on some old-school and low scopes. So like I Really Don't know why modern digital scopes don't have alternate trigger as such and call it as such because it's actually really quite handy. but this keysight one does actually have it in addition to pattern triggering as we'll see and be they're on the same time base. They are genuine, like this one is genuinely half the length of that.

This is not a dual time-based scope which I might have to go into anyway. That's another rare feature of scopes these days. We can actually go in there and measure various things if we want, and you can muck around to your heart's content and you can get both on the screen at once. It could be really handy.

essential Phoenicia applications, and by the way, it may not just automatically work like this. You may actually have to go into your trigger menu down here, and you may actually have to change your hold off like this depending on your signals in the distance between them and stuff like that. If we take that out far enough, we'll probably see one vanish. Yep, they are.

And yep, we have a way of calming. Guts are and the other ones vanish now. and sometimes you've got to have it yet. Twiddle around with it or we can do random hold off.

well. I Like to see how the random hold off anyway. if you don't know about trigger hold-off probably done a video on that have I Anyway, Um, basically it'll take the first trigger, then it'll wait. It'll hold off for a certain number of milliseconds before it arms itself again before it cannot trigger the next one.

Anyway, this is probably not the best example for that, but you may have to twiddle around with that and this would actually be a classic use case for segmented memory as well. So if we go into our choir menu and we go segment of memory, let's set up say a hundred segments. Segment A memory. Boom.

It's captured and then we can just scroll through those and you can see how it's capturing those alternately. So yeah, there you go. It seems to be doing proper alternate triggering. one.

You can see the the frame, it just open eights between those two channels like that. If if you get out of segmented mode and just single-shot cache right then it's just going to be. It's going to appear random. but it is actually doing an alternate or trigger great.

And this siglent 1104 XC here. we can actually get it working, but we have to use a pattern type. We don't actually have a specific or slash unit treeger function, so we're going to use a pattern which is designed for digital and can actually get in there and set those and I set them both too low. Ironically I can't actually set them both too high.

It doesn't work, just goes all over the place. But low will get that to work. so we can't actually kludge that using what's designed to be a digital logic function. Now in this particular case, we happen to be using digital or waveforms here so you could come and guts completely on that.

with other types of waveforms, we just happen to be able to get this, you know, to kind of sort of work and we should be able to see this because most scopes have pattern triggering on them these days so you can sort of get it. but just remember it's not the same as proper or triggering that we saw on the keysight one. Now you can't achieve this same thing on old school analog scopes. Unfortunately, my taketake 2465 which ever fully repaired yet I didn't realize this, but the the B time base is actually buggered on it.

Anyway, you can see that there's our options for B trigger delay hold off so we could potentially get both on the screen at once there can the road and Schwartz RTB mm do it. Well, let's going to trigger types here. Looks like it doesn't have it. but pattern triggering? Whoa-ho Fancy pantsy.

Just like the Aki site, all of the digital channels, the four analog channels, and we've gotten and or all function. So it's basically and we can set those going true. and if we do that, Ego works an absolute treat. There's a little bit of you know, flickering action happening there.

Now it's stupid. Me's in auto trigger mode. You need normal trigger mode I Suspect that might work. No, it's still the same.

We might have to use hold anyway. you shouldn't use auto trigger mode. should be using normal because you don't want the auto trigger to accidentally trigger when you don't really intend it to. Seems a little bit better there.

I do the whole time. it just sends a function of the or pattern on this particular scope. Anyway, does the business and this. R I go RDS mm series scope here.

we can get it working on. the pattern. Mode here says to be a bit quirky. you can't actually select both the rising edge on both of it, but I was able to get it work in both of them on low like that.

So yeah, that's the business and the venerable Des 1054 ZD do have a pattern option down in here. Let's go check it out. Well, lots of relays clicked anyway. Yep, we can.

Looks like we might be able to do the business once again. The DS 1054 Z I cannot set both of them to gain an edge type, so there's some sort of weird limitation Anyway, if I said both of those too low. Winner winner chicken dinner. But let's take a look at an interesting scope here: the Unity Upo 3000 E series among a couple of other scopes on the market including the I believe the original Roy Goldie's 1052 II not the said the old in the old-school emod 'el which I reviewed in Eevblog number one video that actually has a feature called dual time base.

So if we actually go into the horizontal menu here, let's have a look. Time base is normal. okay. but if we go in there and select independent time base, what we get now is you can see we've got four independent time basis for the four channels.

We don't need three or you can't actually turn that off Really? Wow Okay, Function disabled. Oh, it forces all four channels on. That's kind of weird. Didn't know about that.

Anyway, we have an independent time base, so if we select channel one, we can adjust the time base independently on channel one. and if we select channel two, we can independently select that and it's triggering off the two different ones. Of course, the advantage of having different time bases for each channel is that we can see as much detail as we like. Isn't that absolutely fantastic? But just be aware there are different time bases.

so if you're going in there and you know measuring stuff like visually off the screen, then you can potentially come a guts are there forgetting that you've got the different time bases. but these are dual time base scopes or you know, reasonably rare on the market. So, but this unity happens to have it. There's a couple of other models out there let us know if your one has it, but anyway, this does the business without having to muck around with your triggering because by default, when you enable a dual time-based scope, it has a separate trigger for each one.

It's actually triggering off channel 1 and channel 2 totally independently. So technically, dual time-based scope is better than the alternate trigger system because if now, if we actually single, if we stop that, or if we single-shot capture, that will actually get both at the same time. Oh Single shot capture. Come on.

I'm pressing the single button I Swear. single function is disabled. You can't Oh my goodness. I hadn't used the scope in depth.

Unbelievable. Single shot capture mode disabled in dual time base. Your time base scopes are great, but for some reason manufacturers well you know it's more complicated. so you know the reason why.

It's more complicated to implement a proper joule, time base and your independent triggering system, but it's really handy so that's pretty neat. And I Do believe the Tektronix entry-level the TBS or Tech Basic Scopes series also has dual time base as well. GWS Tech GDS 1000 series that doesn't have the triggering and our Tektronix MDO 3000 here. Yep, sure enough, it has logic down here so we can go in.

We can define our inputs exactly like the keysight and the Road and Schwartz and we can set both to high. Like that, we can define our logic as or trigger when goes true and you can set up your thresholds and stuff as well. And there we go. That works.

It's a little bit sort of clunkier, but it does the business. And I have to set the thresholds up here. As you can see, if you adjust the threshold, you can see the Channel One threshold going up and then Balma channel one is Gonz Gonski because we don't have the independent threshold set, so just be aware of that. when you're playing around with it trying to get it working.

you need both of those thresholds. And how about the siglent STS 5000? Well wow, I got a pattern here. Let's see if we can do the business on that. but in logic? Oh yeah, there we go.

Or yep, here we go and it disables the ones we haven't got on nice so we'll go high. We'll go high. We can set the independent level values that's too low. We need to tweak that up a bit.

Oh yeah, no no, it's all good. and yep, that works A treat that beautiful. Bobby Dazzler And once again, it's not your time base. We're only capturing one of those at the time, so it's alternate trigger or it's going.

or actually out of all the Scopes that did that. I Think the the key site and the siglent both give the nicest, most responsive display on that. If those playing along at home, you want to know that anyway and check this out. The O1 XDS 3200 This one actually if you go into the trigger menu here.

Edge: Okay, if you want a single if you go into here, nothing there but look old alternate trigger straight in. Beautiful and it also supports logic as well as setup logic with the all mode here and XOR and Xnor and and and of course and will never work because they're never both true at the same time. You saw that on the main time-base so you can set. that goes true so that one's actually got the true alternate trigger mode isn't that new.

I Like that you can't single shot capturing alt mode though, but you can run, stop, and get both at the same time. Winner! So only one of my scopes seem to have had like a proper old-school alternate trigger mode even though you couldn't do it in single mode. and the key sight is the only one that has both pattern and or and of course the pattern one does work but the all one. You can set both of your channels or you can basically set all of your channels to slopes where you can't do that.

and I Found this pretty consistent across all the other scopes as well. If you go in, the pattern triggering, you can only set and it does actually tell you this in the manual if you read it that only one of them can actually be a rise in edge. So check it out right if I try and set the first one to a rising edge I Can do that. Try and set the second one to a rising edge your card.

You can only have one as a rising edge which I Don't really know why that limitation exists. If you do know, please leave it in the comments. But anyway, just bear in mind that if you're using pattern trigger on your scope and it doesn't have a true alternate trigger or an all function like this site key site, then really, it's only good for digital channels if you're trying to do this on analog waveforms. Yeah, you may not be so lucky.

So there you go I Hope you enjoyed that and found it useful. If you did, please give it a big thumbs up and share the video and all that sort of jazz because that really helps a lot cuz YouTube algorithm kind of sucks these days. Doesn't really share very well Anyway, as always discussed in the comments or over on the EEV blog forum catch you next time.