Products > Test Equipment
Analog vs digital X-Y mode
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bd139:
Someone should try this on an HP 546xx. They have a superior X-Y mode. Not bad for 1994...

https://youtu.be/D2uEvRPd4w8
chris_leyson:
Nice tutorials from Jerobeam Fenderson
nctnico:
At least some DSOs can do color grading in XY mode:
JohnnyMalaria:
I've put together a short sequence of videos to show why an ancient analog scope beats the crap out of a budget DSO in XY mode. There's no audio but there's a description which I've included here, too.




--- Quote ---Budget digital storage oscilloscopes offer many advantages over analog CRT oscilloscopes but one area they suck at is XY mode.

This mode is important for looking at, for example, rotation of quadrature signals in the complex plane. This short video has back-to-back clips of an XY signal rotating at different angular rates. The analog oscilloscope is a Tektronix 475 manufactured in 1974. The DSO is a Rigol DS1104Z manufactured in 2017.

The first two clips are slowly rotating and the two oscilloscopes compare very well.

When the rotation speed of signal in the second example is increased, the DSO simply gets in wrong. The direction of the rotation is incorrect as is the speed. This is because the DSO captures a finite amount of the signal and displays it once complete.

In contrast, the analog oscilloscope displays the signal in real-time without interruption. A good analogy is the effect of video or film frame rate on the appearance of rotating aircraft engine propellers or rotating spoked car wheels. There's no way to tell if the observed rotation speed and/or direction is correct.

At much faster rotation speeds, the DSO yet again presents misleading information (clip 4).

Clip 5 shows how the DSO XY mode doesn't display significant amounts of the signal and the signal it does display lacks the extraordinary detail shown on the analog oscilloscope.

Finally, clip 6 shows that the DSO displays all of the signal but at a much lower resolution than the analog oscilloscope and the rotation is in the wrong direction.

It is common to compare these types of oscilloscopes using simple Lissajous figures but, frankly, the only real application of this is in 1950's sci-fi movies. Looking at changes of XY signals in the complex plane involves much more complex signals with intricate detail.

The analog oscilloscope may be 43 years older than the DSO but for budget DSOs, the analog one beats them by miles.

Professional grade DSOs generally offer far superior XY rendering than the budget ones but you can't beat the real-time, continuous and varying intensity of the analog equipment.
--- End quote ---
alsetalokin4017:
Well, to be fair, it is possible to get a _slightly_ better display of the ScopeClock on the Rigol DS1054Z than what was shown in the OP.

But it definitely looks better on the analog scopes.

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