Browse Prior Art Database

Test Pattern Generator

IP.com Disclosure Number: IPCOM000042816D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

McDowell, AW: AUTHOR [+2]

Abstract

This circuit arrangement generates a customer-recognizable test pattern on the screen of a monochrome display unit which has been adapted by installation of an analog switch unit for connection to a personal computer logic element having either monochrome or color output signals. The test pattern generator allows the analog adjustments in the display unit having to do with the analog switch unit to be made without the presence of the personal computer logic element. Further, the test pattern generator facilitates problem determination by isolating a problem, if one occurs, as coming from the display unit portion or the personal computer portion of the completed assembly. Fig.

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Test Pattern Generator

This circuit arrangement generates a customer-recognizable test pattern on the screen of a monochrome display unit which has been adapted by installation of an analog switch unit for connection to a personal computer logic element having either monochrome or color output signals. The test pattern generator allows the analog adjustments in the display unit having to do with the analog switch unit to be made without the presence of the personal computer logic element. Further, the test pattern generator facilitates problem determination by isolating a problem, if one occurs, as coming from the display unit portion or the personal computer portion of the completed assembly. Fig. 1 illustrates schematically the relationship of the display unit 10 and the personal computer logic element 12, the functions of which are to be tested and simulated, respectively, by the use of the test pattern generator 16. Also shown is an electrical schematic of portions of the display unit 10 which are relevant to the operation and use of generator 16, and fragmentary showings of the cables 18 and 18', with their connectors 20 and 20' coupled to the connectors 22 and 22' of the display unit 10. Cables 18 and 18' connect display unit 10 to logic element 12 in normal operation, and could be combined into a single cable if the personal computer logic element 12 is constructed in that manner. The elements of display unit 10 shown include a refresh buffer and character generator 24 having outputs on bus 26 which, in normal operation of unit 10, are connected through an analog switch unit 28 to the corresponding inputs of analog circuitry 30 driving a CRT display 32. Analog switch unit 28 receives another set of inputs by a bus 34 connected to cable 18, for use instead of the inputs on bus 26 when the display unit 10 is operating in its personal computer mode. For this purpose, connector 22' couples a select...