Vector display system

Claim 2

In apparatus for controlling a device to display a straight line from a present position to a new position, where said positions are defined digitally in a rectangular coordinate system, and a given point is displayed on the device in response to a pair of deflection signals proportional to rectangular coordinates of said given point, the combination comprising: means for converting present position data into first and second analog signals proportional to present position coordinates X and Y; means for generating a ramp signal; means for multiplying said ramp signal by the coordinate differences Delta X and Delta Y between said present position coordinates and new position coordinates to provide third and fourth analog signals; and means for adding said third and fourth signals to said first and second signals to provide said pair of deflection signals.

Claim 3

The combination of claim 1 wherein said ramp signal generating means includes a plurality of capacitors which may be selected for integrating current from a constant source including apparatus for making the ramp rate of said ramp signal approximately inversely proportional to the length of a given line to be displayed by selecting combinations of said capacitors comprising: means for determining which of the differences Delta X and Delta Y is larger, and selecting the larger as a value L in digital form and the other as a value S in digital form; means for forming a composite group of digital signals by combining with one group of digital signals of said value L, another group of digital signals of said value S; and means for selecting said capacitors in response to said composite group of digital signals, where each of said capacitors selected by a digital signal of said one group of digital signals of said value L is weighted in proportion to the numerical weight of the digital signal by which it is selected, and each of said capacitors selected by a digital signal of said other group of digital signals of said value S is weighted in proportion to approximately 0.375 the numerical weight of the digital signal by which it is selected, thereby maintaining the rate of change of said pair of deflection said pair substantially constant.

Claim 4

The combination of claim 2 including means for scaling the coordinate differences Delta X and Delta Y before forming said composite group of digital signals, thereby sealing said ramp rate in proportion to sealing of said coordinate differences to reduce the range of ramp rates required for a given range of differences Delta X and Delta Y.

Claim 5

The combination of claim 3 including control Means for rendering said device responsive to said deflection signals as said ramp signal starts to increase from zero volts, and means for terminating the response of said device when said ramp reaches a predetermined level.

Claim 6

The combination of claim 4 including means for scaling said predetermined level by the reciprocal of a factor by which said differences Delta X and Delta Y are scaled for said given line to be displayed.

Claim 7

The combination of claim 5 wherein said device employs an electron beam deflection system to display a line in response to said deflection signals, and said control means comprises means for delaying the turning on of said beam for a predetermined time while said ramp signal increases from zero, and means for delaying the turning off of said beam for a predetermined time after said signal reaches said predetermined level, thereby compensating for lag in the response of said deflection system to said deflection signals.

Claim 8

The combination of claim 6 including means for initiating said ramp signal at a level below zero.

Claim 9

The combination of claim 7 including means for selectively inverting said third and fourth analog signals for negative differences in components Delta X and Delta Y, respectively before said third and fourth signals are added to said first and second signals to provide said pair of deflection signals.

Claim 10

The combination of claim 1 including: means for scaling the coordinate differences Delta X and Delta Y to assure that at least one of the differences will be equal to or greater than a predetermined number; means for determining the approximate length of a line defined by said scaled differences, and in response thereto for making the ramp rate of said signal inversely proportional to said approximate length; first control means for rendering said device responsive to said deflection signals when said ramp signal starts to increase from zero volts; second control means for terminating the response of said device when said ramp reaches a predetermined level; and means for scaling said predetermined level by the reciprocal of a factor by which said differences Delta X and Delta Y are scaled.

Claim 11

The combination of claim 9 wherein said devices employs an electron beam deflection system to display a line in response to said deflection signals, including means for initiating said ramp signal at a level below zero.

Claim 12

The combination of claim 10 including: means for delaying said first control means in rendering said device responsive for a predetermined period; and means for delaying said second control means in terminating the response of said device for a predetermined period; thereby compensating for lag in the response of said deflection system to said deflection signals.