Hi Welcome to the Eev blog! an Electronics Engineering Video blog of interest to anyone involved in electronics Design. I'm your host Dave Jones Hi No. I'm not in the lab today I'm in the lounge room. Why? Because I've got my old Uh analog Hmeg analog oscilloscope hooked up to my desktop computer.

As you can see, there's the probes up there, they're connected to the Uh sound card output uh signal from the desktop which is is Um which is actually my media center. it sits in the cabinet behind there and I'm running the famous Uscope demo which gets some pretty funky displays on here. As you can see, it's got scrolling text and really uh, funky images. Check this out.

there it goes. unbelievable and you can get this on an analog oscilloscope. Now this Uscope demo. it's not new.

It was uh developed by a 15-year-old kid I believe as part of an Assembly Language programming contest in 2007 and everyone Um has played with this before. It's really fun! I Highly recommend you download it. What it is is a sound file. It's just a wave file that generates Uh signal that generates waveforms on the left and right channel of your audio card and they're fed into your oscilloscope into the XY mode and as you'll know so the left channel into X Y into right or so for and uh as you can see, you can generate text and uh scrolling images and all sorts of you know rotational cubes and really funky display in XY mode.

And if you don't know how XY mode works, basically the X Uh input controls the voltage on the input controls where the dot is on the screen um, across the x-axis and likewise the Y input. Uh, down here the voltage on that controls the dot in the Y axis so there is no time base anymore. It is a direct correlation if I take out the input signal here as you can see, it's just a DOT on the display like that. and if I plug in the Um, X and Y inputs as you can see away it goes and it generates the image based on that.

Now um, it's really funky because it doesn't. There is no way to blank that signal. Okay, normally some oscilloscopes have a z axis input uh and that will actually turn off the dot for a brief period so you can move the dot around. You can draw lines like a vector-based display, but then you can turn it off.

but this use scope demo is great because it doesn't use that. Um, so hence if I turn up the brightness here you can see the lines that are used to actually draw it. so you've really got to get your your intensity just right so that you don't see those flyback lines. all you see is the actual animation.

Now there's nothing new here but I Thought that I'd try and get this working on a digital scope and see what happens. So let's give it a go. And the reason I'm using my desktop computer here is that uh, you really need a good quality sound card with a line out it I found it doesn't really work on the headphone uh, outputs which is all my notebook computer's got. So and here you go.

as you can see, it works and which is isn't really surprising given that uh, this is $50,000 waveform updates per second on this Agilant scope. You can actually quite clearly see it, but it actually works too good because you can see all the flyback lines. Now if I vary the intensity, if I drop it down. you can still see the flyback lines on there, which is quite annoying.

I can turn it all the way up of course and get maximum intensity and uh, but you can still see those flyback lines and it, You know it. It really is a little bit, uh, really is a little bit annoying so you can't really get rid of that. It's too good. You can't sort of drop the intensity right down and see and that's like zero.

You know that's with the intensity right down. I Can see the display quite nicely, but you can still see the flyback lines and I want to get rid of those? so let's see what we can do. So here's a little trick we can use to get rid of that display. Now what I'm going to do is I'm going to turn on the uh, infinite persistence.

So I'll go into persistence mode and turn on infinite persistence. And okay, what I'm going to do is I'm going to let that fill up the display. There we go, it's filled up the entire background display with that color there. Now as you can see, we're left with uh, if we turn it back down to scale, we're left with the uh, the actual image we can see quite well.

But what happens is you actually get to a point where if you change your intensity over here, okay, if you turn it all the way down, then you can still see the flyback lines on there, which is really quite annoying. But if you take it all the way up, there will be a point where those flyback lines disappear and they become the same color as the background. Watch this and Bingo there it is. It's A at about 84 or 85% intensity for this particular scope and setup, and if I turn it past that as you can see it, you know the flyback lines become completely, uh, completely visible and they're hopeless.

But it reaches a point where it goes from that negative to the positive and it matches. and I think that's about 84% So I'm going to leave it at that and Bingo! We've got our nice U scope display on a digital scope. I Love it And and I know what you're thinking. What does it look like on the Ryol on a like less than sub 1,000 waveform updates per second scope.

As you can see, it's pretty darn crap and there's not much you can do about it. uh, at all. It just it just can't cut it. You can kind of sort of.

There's that animation display on there. it just really can't do it. It's hopeless, so that's no good. Let's watch the full version of the Uscope demo on the Agel scope in En Joy I I I A.