System Layout diagram

heres the current big picture as to what goes where in the system.as time goes on ill draw up the schematics for each module on a computer (theyre all scrawled in a notebook atm) and post them up here.

A post about the chassis design.

the chassis for all the modules is very simple: its a piece of plywood with these aluminium boxes from Maplin's screwed to them. the PCBs and controls are mounted in the removable lid, thus making it fully modular. power cabling runs along the back of the plywood which also gives extra mounting space for power supplies, sync distro, etc. i put it together of a couple of hours, so its really very easy to build too. i guess i should draw up some proper plans and post them somewhen soon.

its a very strong but lightweight system, and as all the modules are sheilded from each other with at least 2 thicknesses of well grounded aluminium between them im hoping it should also provide excellent RF shielding. my 12 module unit cost me less than £100 to put together, including a load of 40mm aluminium angle (3mm thick) that ill make rack ears out of. it doesnt fit in a standard 19 inch rack, but i can make whatever wooden case to go around the main unit as and when i feel like it and use standard rack mounting strips to hold it in place.

i have many audio analog synth pcb's that have been waiting to be cased. ill use this method with them as well.

Another Video

feedback, live camera feed (black and white security cam found in a bin) and oscillators and mixing from the synth. the sync feed to the camera has been pulled which gives it the scrolling across the screen effect.

More VidSynth Pictures

heres a shot of the video synth as it is today - its leaning against the effects rack with the old modular synth on top.

the three modules running across the top of the cabinet are the oscillators. they are based on the venerable and much loathed XR8038 chip. i like it. the flux capacitor shaped module in the centre is a 3 channel arbitrary function generator and the one to the left is a 3 by 3 mixer matrix. heres a pic of the guts of one of the VCOs

a note about the jacks - they're not BNCs but frankly i dont care. it works. the hookup wire is RG178 super skinny video coax. pots and switches are surplus from somewhere or other, and the pcb is home made. note the extra capacitors tacked on the board for more power supply goodness. yay prototypes...

Video Demo

heres a short video - live input from a black and white camera, processed and mixed with some abstract video from the synth.

Prototyping

heres a shot of the synth that made the previous screenshots ..

its a large format modular synth that has been built over the last ten years. its mostly based on EFM circuits and CEM chip applications notes. the EFM modules are remarkably adept at working at frequencies far exceeding the audio bands... well, the ones that didnt explode due to user error are anyways...
the video encoding hardware is in a seperate rack that consists of various 99p ebay bargains - broadcast grade rgb to pal, component to pal and pal to everything encoders and decoders, 2 sync pulse generators, various genlocks, mixers, switchers, VDA's and an oscilloscope. ebay rocks.
its a great time to pick stuff like this up on ebay. all the pro broadcast facilities in the UK are dumping their analogue gear as the digital switch-over approaches. a lot of it ends up on ebay, where it generally goes for bugger all & buyer collects. as most of the facilities are based in London, its not hard to cycle down to Soho with a backpack and a shiny one pound coin to pick up, for instance, an NTSC sync generator full of Sandin IP MC1445 video multiplier chips....