MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

Solarizer, Posterizer, and Inverter Circuit
MUFF WIGGLER Forum Index -> Video Synthesis  
Author Solarizer, Posterizer, and Inverter Circuit
wcfields
Been poking around the North Country Radio site (they make the Video Palette II kit) and came accross a schematic they had for the FX board for the original here as published in R-E OCTOBER 1987.

Part 1 & Part 2 of the articles.

I was wondering about building a circuit that only uses the FX units and skipping the mainboard and only using the below FX circuit as an Input/Output in the LZX system.

Would this be possible (assuming that I can source some of the obsolete IC's), or will I run into sync issues? I am curious if sync will play an issue since these are only waveform transformations.

If not, would it only be possible removing the Sync Separator circuit and tie into the LZX Video Sync Distribution for this application?


fletch
I brought this up in a previous thread, haven't really done much with the device since then. The consensus seems to be that it's a really finicky device, and hard to rely on because it takes such fine tuning. The effects do look pretty nice though.
lizlarsen
You could make it work. Most of the circuitry involved here has to do with the DC restoration, sync separation, sync restoration, etc. though -- things that in an LZX system, are already taken care of by the Sync Gen and Color Encoder modules.

For the inverter & solarizer, you're better off just DIY'ing up some Sandin IP Function Generators for your LZX system. That is a 3-level solarizer and inverter with lots of uses and more powerful than this circuit.

For the posterizer, that's kind of an amplitude classifier but less versatile. A much better candidate for adaptation is the DIY colorizer circuit the "VISUALIST by berto" -- since it spits out RGB already! Just cut out the color encoder, video input, and sync separator portions...

https://s3-eu-west-1.amazonaws.com/bertoa/VisualistKl.pdf

I need to upload the final schematics for the IP stuff to the LZX site, I'll do that soon.
wcfields
creatorlars wrote:

For the inverter & solarizer, you're better off just DIY'ing up some Sandin IP Function Generators for your LZX system. That is a 3-level solarizer and inverter with lots of uses and more powerful than this circuit.


Sounds better, I'll try experimenting with CV controlled Varicaps. An LFO controlled inverter would give a nice (or really annoying) strobe effect.

creatorlars wrote:
For the posterizer, that's kind of an amplitude classifier but less versatile.


Ah, that makes sense. Thanks for helping understand how these effects 'work'.
lizlarsen
Quote:
Sounds better, I'll try experimenting with CV controlled Varicaps. An LFO controlled inverter would give a nice (or really annoying) strobe effect.


A crossfader (either TVFKG, or roll your own with the LT1251/LT1256 chip) is what you want here. That's what I always use when I want voltage control between inverted/non-inverted, like in this video -- I patched up a very complex shape patch, keyed it out, and then used that as a CV key to switch between inverted/non-inverted versions of a source feed:


Triple Video Processor, Function Generator, Video Blending Matrix can all invert a video.

Quote:
Thanks for helping understand how these effects 'work'.

No problem. That "comparator chain" in the posterizer is similar to what you'd find in any amplitude classifier type circuit -- it's just the outputs go to static gray levels rather than separate outputs which can then be mixed to colors. In the Sandin IP Amplitude Classifier design, the outputs control VCAs, which makes it even more powerful.
nickciontea
creatorlars wrote:
I patched up a very complex shape patch


no kidding. screaming goo yo
daverj
If you are using signals already inside a video synth (LZX or Jones), you don't need any of that first board. The effects board is just processing the signal portion and doesn't have to worry about sync. The rest of the video synth takes care of that.

The MC3430 quad comparators are obsolete, but any video rate comparators will work, such as LM319. (those need pullup resistors on the output pins since they are open collector)

An inverter is super simple. Any video op amp will work, and you just need the standard inverting op amp circuit. Since LZX video signals are unipolar you need to add a bias resistor to get the inverted video back up to normal levels. Jones video is bipolar so doesn't need that. So 2 or 3 resistors and a video op amp gets you an inverter. It would be simple to have several of those in a small module.

What they call a "Posterizer" is a simple quantizer. Quantizers are super simple circuits, and there's something nice about that simplicity. No adjustments, no frills. Just video goes in and comes out with limited shades of gray.

Quantizing a composite color image can get you some pretty seriously strong colors on those shades of gray, if you go out through one of my output amps. The quantized subcarrier is lost if going out through an encoder. On the other hand you could set up the quantizer with separate outputs on each comparator and feed those into mixers or straight to different inputs on the encoder and get all sorts of overlapping colors. Alternately you could feed the comparators into a priority encoder chip, like in the schematic Lars linked to, which gives you a binary encoded output. With that, each combination of the individual outputs is unique and not overlapping, so you would get unique colors for each shade of gray when going to an encoder.

A solarizer is also a simple device, and the Sandin function generators are certainly more controllable than the one on that effects board.
pulse_divider
Lars, is that Alphaville? SlayerBadger! SlayerBadger!
lizlarsen
Yes, it's Alphaville.
MUFF WIGGLER Forum Index -> Video Synthesis  
Page 1 of 1
Powered by phpBB © phpBB Group