SYSTEM FOR PRODUCING CHARACTERS ON A CATHODE RAY TUBE DISPLAY BY INTENSITY CONTROLLED POINT-TO-POINT VECTOR GENERATION

摘要

An alpha-numeric character generating system receives digital codes representing characters and controls a CRT to trace a plurality of vectors which in combination form the characters displayed. A read-only memory provides in sequence a plurality of sets of X, Y and Z parameters for each character. Succeeding X and Y parameters are each stored in corresponding alternate registers. The sets of X and Y parameters define the end points of the vectors forming a character. Two digital to analog converters responsive to the X and Y parameters, respectively, provide signals for deflecting the CRT beam. The inputs of the digital to analog converters are transferred between corresponding alternate registers to cause the CRT beam to trace from one vector end point to the next in sequence. A toggle circuit responsive to the Z parameter associated with each set of X and Y parameters controls the transfer time between registers and thus the brightness of each vector traced on the CRT screen.