A patch for Rutt-Etra style scan processing with an XY display

Visual Cortex, Navigator, Bridge, Passage, Shapechanger

Additional Equipment needed:
Monochrome CCTV Camera
XY Display

  1. XY Signal Flow
    Navigator and Shapechanger are used to process H & V ramps before they are sent to the XY display. This allows control over XY position, rotation, width, height, curve, and skew of the resulting vector image.

Patch Visual Cortex - Ramp Generator - Vertical Ramp Out to Navigator - IO - Vertical In
Patch Visual Cortex - Ramp Generator - Horizontal Ramp Out to Navigator - IO - Horizontal In
Patch Navigator - IO - Horizontal Out to Shapechanger - IO - Horizontal In
Patch Navigator - IO - Vertical Out to Shapechanger - IO - Vertical In
Patch Shapechanger - IO - Vertical Out to Tektronix 620 XY Display - Y In
Patch Shapechanger - IO - Horizontal Out to Tektronix 620 XY Display - X In

Shapechanger - Other Controls - Gain Select, Scale Mode (Up), %
Navigator - X Position - Mode Select, Anchor (Right), %
Navigator - Y Position - Mode Select, Anchor (Left), %

  1. Luma Processor
    In this subsection, Passage channel #1 controls the contrast of the image and Passage channel #2 controls the brightness of the Luma image. There are several approaches to achieving this, and this is only one of them. If your XY display requires a higher gain signal on the output, use the Bridge amplifier/multiple in X5 gain mode at the final output. If your XY display needs an inverted signal, you can use the Bridge Mixer with Negative mode on to do this.

Patch Monochrome CCTV Camera - Video Out to Visual Cortex - Input Decoder - Y In
Patch Visual Cortex - Input Decoder - Luma Out to Bridge - Fader - B In
Patch Passage - Channel 1 - Output to Bridge - Fader - Voltage Control In
Patch Bridge - Fader - Output to Passage - Channel 2 - Thru
Patch Bridge - Multiple 1 - Out 1 to Tektronix 620 XY Display - Z In
Patch Passage - Channel 2 - Output to Bridge - Multiple 1 - Input
Passage - Channel 1 - +/- Brightness, 92%

  1. Luma Displacement
    The classic Rutt-Etra effect is achieved by modulating position with the luma signal itself.

Patch Visual Cortex - Input Decoder - Luma Out to Navigator - Y Position - Input
Navigator - Y Position - Y Position Control, 22%
Navigator - Y Position - +/- Level, 82%


It’s always a good day for Bach imho. Here’s my re-variation and themes from his Lute Suite in C Minor re-combined with shapes and images found when my LZX Industries video synthesizer met and played with a damaged Tektronix XYZ scope. I could sort of do Rutt-Etra style rescanning (as described on this page: A patch for Rutt-Etra style scan processing with an XY display ), but not quite.


Im having a hard time finding Tektronix 620 X-Y displays, what other display would you recommend?

Unfortunately when it comes to sourcing a vector display, you’ve got a journey ahead of you. It can take a while to find one in the first place, and I’d say most of us buy 2 or 3 before finding one that’s working well for our needs (or just working well in general!) Keep your eye on eBay and search for “XY display.” Avoid things called vectorscopes – that’s something different, even though they look similar. Tektronix made several models. HP Agilent did as well IIRC.

Would any of the oscilloscope models from Tektronix work?

Yes they might! Vector monitor sourcing is a good topic for a different thread though, as we could go on forever. :slight_smile:

key word used by lars: might


Also having a hard time finding a Shapechanger is there another way of achieving the Rutt-Etra scan processing effect without this module or a different module?

There’s many ways to patch rescan processing – it’s more of a technique with auxiliary needs than any one way to do it. This just shows you how to set up an example patch. Best advice is to get Visual Cortex and start searching for the right XY display while learning how to patch the system. Shapechanger will be around again before long. You will be able to get a rescan going on an XY display just with Cortex; the other modules just expand upon processing options.


so would something along these lines work for display purposes?

I have a feeling that some of those plugs are mechanically disconnected inside as a couple of them don’t do anything
I was thinking about popping it open and having a look see

I see X,Y and Z inputs although I seem to remember reading that the Z input was expecting more voltage in the range of ± 10v I think
perhaps I could use the bridge to scale up as was suggested

I can get some fun things to happen when plugging a prismatic ray into the H-input ext. sync and having the horizontal selector on external

I’ll try to get a video up :slight_smile:

I found a sort of cookbook for how to patch a cadet system for vector rescanning at http://rutt-cadetra.blogspot.com/2017/12/normaled-connections-acrylic-panel.html

It worked fine for me as a starting point to get going. I just used the luma section of my vidiot to process the luma distortion of the horisontal lines going int th the in on C7 doing the Y processing.

Beeing a novice im not completely able to understand what is going on under the hood, but it seems that i get adequate results with lesser complexity if i only process each of the V and H ramps through one C10 instead of through two that this cookbook mentions. Somebody correct me, and enlighten me as to why i would want to go through two multipliers before going to the C7s?.

Thought i would post this here for people having or thinking about building Cadets for the purpose of vector rescanning. :slight_smile: It at least helped me build and use my newly built Cadets for something usefull:


Best. Lau


Hi there folks, so I have a Tektronix 608 and tried a basic patch along these lines today. No matter what order I put the ramps in, which combination I selected on the Cortex, changing the rotation on the back of the scope the image was still either 90 or 180 degrees out (e.g. the top of the image was at the bottom). Any thoughts on hat this could be? Many thanks!

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flip. that. rescan. camera. !!!
free rotation
I haven’t actually done any rutt etra stuff but that would be my path of least resistance answer


that is some -out of the box- thinking for you! :grinning: