Browse Prior Art Database

End Point Vector Generating System

IP.com Disclosure Number: IPCOM000095674D
Original Publication Date: 1964-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Lamoureux, WR: AUTHOR [+2]

Abstract

In a CRT Display System having alphanumeric and vector generating capabilities, it is desirable to display vectors of varying length by controlling the time constant of the yoke as a function of the vector length. An alphanumeric character generator invariably requires short precise strokes for each character, while other vectors can vary to full screen size. For maximum efficiency, it is desirable to draw and space characters within a certain time increment, medium length vectors within a second time increment and long vectors within a third time increment.

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End Point Vector Generating System

In a CRT Display System having alphanumeric and vector generating capabilities, it is desirable to display vectors of varying length by controlling the time constant of the yoke as a function of the vector length. An alphanumeric character generator invariably requires short precise strokes for each character, while other vectors can vary to full screen size. For maximum efficiency, it is desirable to draw and space characters within a certain time increment, medium length vectors within a second time increment and long vectors within a third time increment.

In this system, the waveform of the deflection signals is controlled primarily by the LRC time constant of the yoke, which can be varied to suit the specific vector length requirements. Initially, a determination is made by independent control devices, such as a data processing system, as to the display mode to be employed, i. e., character or vector. Digital coded signals representative of the character or vector to be displayed are applied through input lines 10A... 10N to a high speed digital-to-analog converter 1 1. Its resulting output signals are applied via lines 12 and 13 to a push-pull deflection yoke 16. While damping resistors 17 and 18 are shown as potentiometers, an automatic resistor control can be used.

For alphanumeric display, resistors 17 and 18 are set to the critically damped value, allowing high character generator speed and nominal time interval between...