What is a vector scope and what do you use it for?

[cowasaki]

I was just doing a sweep of Ebay looking for a cheap 4 channel scope (I have a decent 2 channel but on occasion could do with 4 channels and sold my 4 channel scope when I bought my new one...Doh...) when I found several Tektronix SDI wfm601A vector scopes.  When I did a search on the internet I saw that they are used in audio and video for wave comparison but basically what do they do and why would you have one?  They are very cheap on Ebay.......

[ebastler]

Here's the datasheet, which describes the various models and gives an idea of their applications:
https://www.tek.com/datasheet/wfm601a-wfm601e-wfm601m
(Open the PDF datasheet. Specs start on page 7.)

They are specialized devices for looking at video signals. Probably not what you want in terms of bandwidth, timebase selection, and vertical amplification.

[EEVblog]

They are designed for analyzing and aligning analog video signals, to make sure all the video voodoo (chrominance) is working right.
They usually have little fixed window markers on the screen. You input a test pattern and if the dots are within the windows then the video components are within spec.

[cowasaki]

Thanks to both of you.

I just hadn't heard of one before.  No use to me as a bit specialist, shame I sold my 4 channel and probably didn't get enough for it....... 

[Harb]

Used mostly in Broadcast TV, they are used to align the colour subcarrier both level and phase with system timing or matching of one vision source with another.... ie colour matching multiple Camera's or sources so they look the same when switched from one source to another......they are usually paired with a WFM (Wave Form Monitor) which displays the Luminance part of the signal (Brightness) so using both you can sort the Brightness and colour of the final output signal .....

[Richard Crowley]

Vectorscopes are used both for calibration and for operational monitoring during video production.

The common SMPTE Color bar image shows a very sequence cluster of pure colors.
From left to right, White (R+G+B), Yellow (R+G), Cyan (G+B). Green (G), Magenta (R+B), Red (R), Blue (B) and Black (none of the above)

https://upload.wikimedia.org/wikipedia/commons/thumb/6/66/SMPTE_Color_Bars.svg/320px-SMPTE_Color_Bars.svg.png

When viewed on a vector scope, each of the colors should hit the small box targets on the vectorscope.

https://qph.fs.quoracdn.net/main-qimg-51a5a0eb346072e1e0ecd14a951edca5.webp

[rx8pilot]

Many years ago....I paid >$10k for those. About 2000 or so.

My first HD camera was purchased about a year earlier for about $105k - without a lens, batteries, monitor, or AC power supply. On top of that, it was 1035i which is a format that never went anywhere but Sony was happy to convert it to 1080i for only $10k. Cool.

 Things sure have changed.

EDIT: This is the SD model....not as expensive and a lot older design.

[DaJMasta]

There can be some use to a more average user just in that a vectorscope effectively is an X-Y mode scope (though without the known-gain input stages, since it's usually adjustable), so it can be useful for some kinds of visualizations.... but if your scope has an X-Y mode, it doesn't have a lot to offer that's different, except for the specialized graticule.

[rx8pilot]

In this case - it is configured for SDI which has to be decoded and mapped to get vector inputs. Outside of TV land.....it is merely a curiosity.