VECTOR GENERATOR UTILIZING AN EXPONENTIAL ANALOGUE OUTPUT SIGNAL

• US 3,772,563 A
• Filed: 11/09/1972
• Issued: 11/13/1973
• Est. Priority Date: 11/09/1972
• Status: Expired due to Term

• Current Assignee: National Computer Services Limited (Acer, Inc.)
• Original Assignee: Ralph D. Hasenbalg
• Inventors: Hasenbalg, Ralph D.
• Primary Examiner(s): Padgett, Benjamin R.
• Assistant Examiner(s): Nelson, P. A.
• Application Number:
  US05/304,942
• Time in Patent Office: 369 Days
• Field of Search: 1J/2970 315/23,24,25,26 235/197,198
• US Class Current: 315/379
• CPC Class Codes: G06G 7/22 for evaluating trigonometric functions; for conversion of co-ordinates; for computations involving vector quantities trigonometric computations using simultaneous equations G06G7/34 for computations in the complex plane; G06G7/20, G06G7/28 take precedence
• CPC Class Codes: G06G 7/28 for synthesising functions by piecewise approximation

Abstract

An improved vector generating electrical system is provided for forming the mathematical representation of a vector. The system is particularly useful for drawing images in any desired pattern on the screen of a cathode-ray tube, whereby the images are composed of a multitude of vector lines having horizontal and vertical components. With the improved system of the invention, the vector drawing speed is not constant, but is an exponential function. One embodiment utilizes suitable switching gates to adjust the time constant of the exponential function at discrete points during the drawing stroke to reduce the vector drawing time as much as possible. In a second embodiment the time constant is changed in an infinite resolution system.

Claims

1. A system for generating X-axis and Y-axis vector signals including in combination:

first circuitry responsive to an applied input signal for generating an exponential X-axis analog output signal in accordance with the relationship (X2 - Y(t) ) (X2 - X1) e t/T, where T is the time constant;

second circuitry responsive to an applied input signal for generating an exponential Y-axis analog output signal in accordance with the relationship (Y2 - Y(t) ) (Y2 - Y1) e t/T; and

utilization means for said X-axis and Y-axis exponential analog signals, said utilization means cOmprising a scanning element, X-axis and Yaxis deflection means for deflecting the scanning element, and Xaxis and Y-axis deflection control circuitry respectively coupled to said X-axis and Y-axis deflection means and to said first and second circuitry for causing said scanning element to scan along a linear path between a starting point and an end point to represent a particular vector as established by the input signals.

2. The combination defined in claim 1, in which the parameters of said first and second circuitry are such that the time constant (T) of the X-axis exponential analog output signal of said first circuitry is the same as the time constant (T) of said Y-axis exponential analog output signal of said second circuitry.

3. The combination defined in claim 1, in which said first circuitry and said second circuitry each includes an integrating operational amplifier circuit.

4. The combination defined in claim 1, in which said input signal to said first circuitry and to said second circuitry each comprises a step function corresponding to the coordinates of a predetermined starting point and end point.

5. The combination defined in claim 1, in which said first circuitry and said second circuitry each includes a switching network for establishing an end point when the analog output signals of said first and second circuitry reach a predetermined minimum value.

6. The system defined in claim 1, in which said utilization means comprises a cathode-ray tube having a viewing screen, means for producing a cathode-ray beam within the tube, X-axis and Y-axis deflection means for deflecting the beam across the screen, and X-axis and Y-axis deflection control circuitry respectively coupled to said X-axis and Y-axis deflection means, said control circuitry being responsive to applied analog signals for causing the cathode-ray beam to scan cyclically across said screen between a starting point and an end point to represent a particular vector as established by said applied analog signals;

and in which said first and second circuitry are included respectively in said X-axis and Y-axis control circuitry.

7. The combination defined in claim 2, and which includes control circuitry for simultaneously changing said time constants as the amplitude levels of said output signals change.

8. The combination defined in claim 7, in which said control circuitry includes switching means responsive to preestablished amplitude levels of said output signals simultaneously to change the time constants thereof.

9. The combination defined in claim 7, in which said control circuitry includes network means responsive to the output amplitudes of said output signals simultaneously to change the time constants thereof on a continuous basis.