Found a Radio magazine article about a display that is based on same CRT tube and probably has same or similar electronics except TV RF part. I need to understand what kind of signal is needed for such display. RPI has multiple video outputs (depending on exact board model). Three potential candidates for this are composite output, DSI (Digital Serial Interface) and DPI (Digital Parallel Interface). Every one of them requires adapting and the analog output might not be the easiest one.

Some more reading:

RGB to composite IC

http://www.analog.com/media/en/technical-documentation/data-sheets/AD724.pdf

Triple video DAC:

http://www.analog.com/media/en/technical-documentation/data-sheets/ADV7120.pdf