Visual display unit with character overstrike

摘要

A visual display unit with character overstrike capability includes a text store in which text is stored in data stream form. A formatter formats the stored text and loads character codes into a refresh buffer which together with a character generator display the characters on a raster scanned cathode ray tube. Control logic responsive to a backspace character combines the bit patterns corresponding to the characters preceding and succeeding the backspace character in a temporary store and then stores the composite bit pattern in the character generator and a pointer thereto in the refresh buffer. The control logic can be inhibited to allow the individual characters constituting the composite character to be displayed individually for editing purposes.