Decca PAL Colour Bar Generator Type EP 686B, a professional television test instrument used to generate standard colour bar and test signals for calibration and servicing of broadcast and studio video equipment. Produced for television engineering and service departments, it enabled accurate alignment of colour balance, signal levels and picture quality in PAL broadcast systems. Widely used by broadcasters, repair workshops and production studios during the era of analogue television transmission; 1960s–1970s.
