Analog Signal Tester for Color Graphic Displays
Original Publication Date: 1988-Apr-01
Included in the Prior Art Database: 2005-Feb-15
A technique is described whereby an analog signal tester is connected to the color graphics display adapter, as used in color cathode ray tube (CRT) displays systems, so as to provide a method of testing the analog output brightness functions of the drivers used in the adapter circuits. (Image Omitted) The color graphics display adapter has three analog output signals corresponding to red, green and blue brightness levels driven by a digital to analog converter (DAC). The tester, described herein, tests the analog signals over their full operational range so as to enable the operation to be verified by a digital system. The tester consists of four comparators 10, as shown in the figure, which are connected to the red, green and blue drive lines 11 of the DAC section of the display adapter circuit card.