A versatile programmable pattern generator.
A versatile visual pattern generator is described that can be programmed by a microcomputer and is developed as a part of a portable visual evoked potential analysis system. The hardware is contained on one printed circuit board (3" X 10", 7.5 X 25.5 cm) residing in an interface connector of a microcomputer (Apple II). The generator produces signals for commercial 50 Hz video monitors; a calibration procedure based on a photocell measurement corrects for the non-linear voltage intensity characteristic of the phosphor of the video monitor.