Circuit for converting digital signals representing color information into analog voltage level signals with enhanced contrast between foreground and background

摘要

PCT No. PCT/US85/02391 Sec. 371 Date Jun. 18, 1986 Sec. 102(e) Date Jun. 18, 1986 PCT Filed Dec. 5, 1985 PCT Pub. No. WO86/03614 PCT Pub. Date Jun. 19, 1986.Circuit for converting digital signals representing color information into analog voltage level signals applied to a monochrome CRT monitor. Digital signals representing color information are applied to first ends of a plurality of resistors (R1 to R4) the other ends of which are connected to a common point (32). The voltage output appearing at the common point (32) determines the analog voltage level signals for application to the monitor. A signal indicative of whether foreground information or background is to be displayed is applied to one end of a further resistor (R5) the other end of which is connected to the common point (32). The value of the further resistor (R5) is so chosen that a relative shift is brought about between the voltage range of the analog signals relating to foreground information and that of the analog signals relating to background, whereby enhanced contrast between foreground information and background is achieved.