I had originally written and posted this on L2O, a social media network project I worked on for almost 4 years. As L2O is being shut down I am migrating a couple of posts here. Since writing this the CCM-3340 was put back into production. http://www.matrixsynth.com/2016/06/curtis-cem3340-vco-chips-re-issued.html
CMOS analog multiplexers were frequently used at the ETC for various purposes. Here I thought I would present a circuit I borrowed from a Dave Jones design, and slightly modified it, to build a black burst generator.
While working for the Experimental Television Center I built the first four Jones Frame Buffers with David. Pictured here is the one I built for myself. The first few buffers where built into the same card racks that were ubiquitous at the ETC at that time, later David rewired most of the buffers into newer larger boxes. This one might be the only one that stayed in the old rack.
This Jones video synthesizer is comprised nearly exclusively of Jones designs. This synth includes a video patch panel made of an inset piece of hardwood with mini-jacks carrying 2vpp differential video. Subsequent modules used Plexiglass. The advantages of this standard is that it limits crosstalk and noise, and making a video signal negative one simply uses a cable that flips the polarity of the wires. It was thought for a time that this system would be embraced by Jones in general, however no synthesizer at the ETC uses the format. The system at the ETC patches standard single ended 1v video through a slide matrix. Using differential video was a great idea but as an unusual standard it only made sense for patching within the panels of multi module synthesizers, and other than a few of the Tuesday afternoon participants, it was an idea that was not really implemented. Unfortunately Jones has yet to manufactured multi module synths as Hearn did.
This was an early Dave Jones keyer. Rich Brewster documented and built it. We referred to this as the black box keyer because it was in a black box. This keyer moved around a bit, at times it was at the center, at times it was at Ralph's studio. I first used this keyer as a student working at the ETC in the converted photo lab studio (at that point the Center was still on Court Street in Binghamton). Years later when I was working for the TV center I lobbied to install it back into the ETC studio.