Modern oscilloscope views: YT, XY but where is XYZ ?

[free_electron]

Hello to all,

Stupid question, years ago I had an old analog oscilloscope, it had not only 2 usual modes "Y versus Time" and "Y versus X", but also had Z input, where I can put any signal to change electron beam intensity and thus vary trace brightness.

As a result I could for example make an simple analog TV from oscilloscope, putting AV signal to Z input and horizontal + vertical raster signals to usual 2 X Y channels.

Nowadays I see no modern 4 channel oscilloscope with this feature.  Oscilloscope makers could for example make a feature, to put 1 and 2 channel to X and Y, then 3rd channel to brightness, (and 4th channel to color of the trace). May be there's no practical engineering application, but this could be a big fun to play with.

Z modulation would require another sampler running at the same time storing an 'intensity byte' per sample. you just doubled your memory requirements and probably did a lot worse when it comes to the processing required for visualisation.

These kind of shenanigans are useless for real applications. if you need this kind of stuff : sample Z with one of the channels ,dump the trace data and send it though some software on the computer.

[mikeselectricstuff]

Z modulation would require another sampler running at the same time storing an 'intensity byte' per sample. you just doubled your memory requirements and probably did a lot worse when it comes to the processing required for visualisation.

But a 4-channel scope will already have this.
I suspect Z-mod inputs were common in the analogue days simply because theye were very easy to implement. Can't say I've ever found a use  for it, though it does allow for some fun playing around

[atmfjstc]

This gets me thinking... if all you have is a XY display, and you're satisfied with isometric instead of true 3D, one could rig up a resistor network to the inputs to project XYZ to XY. The equations are linear, something like:

X' = aX -bY
Y' = aX +bY + cZ

(I forget the exact coefficients)

[Ivan7enych]

These kind of shenanigans are useless for real applications. if you need this kind of stuff : sample Z with one of the channels ,dump the trace data and send it though some software on the computer.

Here is an example of real application.

First picture -
X Y - current probes on stepper motor coils

On second picture I put step pulse from controller to Z input
This highlights each microstep and hides all transitions.

[artag]

your memory requirements and probably did a lot worse when it comes to the processing required for visualisation.

These kind of shenanigans are useless for real applications. if you need this kind of stuff : sample Z with one of the channels ,dump the trace data and send it though some software on the computer.

Fine for static data - Matlab and many other plotting libraries are commonly used for this sort of visualisation. But it's much rarer to do live visualisation in plotting software. The nearest thing to a common computer-based live display is probably chart recorder emulation, though I think I've seen something more like a 3D plot in audio analysis.

It emphasises once again that test equipment shouldn't be closed, single-task stuff. It should be acquisition hardware with a user-programmable UI.