Oscilloscope X-Y Mode - Horizontal Deflection, Vertical Deflection?

Thread Starter

Kurt_051

Joined Nov 11, 2015
6
Hey, folks.

I'm at the very start of a project to figure out how to make my own Oscilloscope art. I've started reading over this guy's blog because he does Oscilloscope art and seems to know what he's doing; in the post linked, he mentions generating an image in an Oscilloscope operating in X-Y mode, and then mentions "horizontal deflection" and "vertical deflection". I have no idea what either of those terms means in a technical sense, have never heard them before, and on a google search am left wanting.

Edit: Found out that I guess it's referring to the deflection plates in a CRO?

Does anybody additionally have any good resources on this, not just "making" it, but understanding from the ground up how to make waveforms with apparent "area"?
 

Hypatia's Protege

Joined Mar 1, 2015
3,197
"Deflection" derives from deflection (via electrostatic, or, less commonly, magnetic) perturbation of the electron beam in 'classic' CRT scopes (i.e. oscilloscopes in which the CRT functions as an instrument as well as a display device)...

As to the remainder of your inquiry -- it's merely a matter of 'cartesian representation' of vectors...

Best regards
HP
 
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Dodgydave

Joined Jun 22, 2012
8,375
An Oscilloscope works by applying a voltage to two plates in the tube, the beam of electrons that is coming from the heater, passes from the Cathode to the Anode through these plates, and the voltage on these plates bends or shifts the beam up or down this is the Y direction, CH1 or CH2.

the X direction is controlled by a built in timebase or oscillator, this shifts the beam left to right,at different speeds.

You need to input an AC signal to the Y plates, and a different AC signal to the X plates to get your Art pictures.

 

Thread Starter

Kurt_051

Joined Nov 11, 2015
6
One of the things I don't get about X-Y mode on an Oscilloscope is how exactly you can get curves that look like they could be represented by parametric equations/fail the vertical line test. Why is it that you're able to make a circle in X-Y mode?
 

Papabravo

Joined Feb 24, 2006
12,389
That is because the functions are parametric, and periodic. What is this vertical line test business and why do you think it is relevant?
 

Aleph(0)

Joined Mar 14, 2015
591
One of the things I don't get about X-Y mode on an Oscilloscope is how exactly you can get curves that look like they could be represented by parametric equations/fail the vertical line test. Why is it that you're able to make a circle in X-Y mode?
Cuz x-y mode deflection is done totally from input signals! Like HP says it just vectors displayed in rectangular coordinate form! I say if you understand parametric equations you should be understanding intro geometry? So for circle on normalized coords is like x^2+y^2=r^2 I say maybe good idea if give yourself practical feel for Lissajous figures before trying to draw them.
 

Aleph(0)

Joined Mar 14, 2015
591
That is because the functions are parametric, and periodic. What is this vertical line test business and why do you think it is relevant?
I say OP just confused cuz if x axis linearly swept like in normal operation would mean 0 time for vertical line and negative time for reversal:rolleyes:
 

Hypatia's Protege

Joined Mar 1, 2015
3,197
One of the things I don't get about X-Y mode on an Oscilloscope is how exactly you can get curves that look like they could be represented by parametric equations/fail the vertical line test. Why is it that you're able to make a circle in X-Y mode?
In X-Y mode the horizontal (X axis) deflection signal is a scaled reproduction of the signal at the 'X' input --- while the vertical (Y Axis) deflection signal is a scaled reproduction of the signal at the 'Y' input...

Thus, for instance, all settings being equal (channel to channel), application of two sine waves (one of each to inputs 'X' and 'Y') being of equal amplitude but exhibiting a phase relationship of ∏/2 will result in a circular display pattern:):):)

Best regards
HP:)
 
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Hypatia's Protege

Joined Mar 1, 2015
3,197
I say OP just confused cuz if x axis linearly swept like in normal operation would mean 0 time for vertical line and negative time for reversal:rolleyes:
@Aleph(0) -- I'm bound to say that a few explanatory words would go much further than "rolling your eyes and shrugging your shoulders"!!! --- If you can't abide the 'students' perhaps you should avoid the 'classroom':cool:

Respectfully
HP
 

dl324

Joined Mar 30, 2015
8,877
Why is it that you're able to make a circle in X-Y mode?
If you input a sine wave for X and Y (e.g. same amplitude and phase), you'll get a circle. By varying the phase you'll get a "rotating" circle. By changing the ratio of the frequencies, you'll get more "humps".
 

Aleph(0)

Joined Mar 14, 2015
591
@Aleph(0) -- I'm bound to say that a few explanatory words would go much further than "rolling your eyes and shrugging your shoulders"!!! --- If you can't abide the 'students' perhaps you should avoid the 'classroom':cool:

Respectfully
HP
HP The op confused about closed figures! So means he not know x and y moment totally controlled by input channels! So he was confused cuz reversing (which also means stopping) impossible if continuously unidirectionally swept! I say there's nothing wrong about my answers and you need chill pill:p!
 
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