Method and system for creating a geometric figure at a selected position on the screen of a cathode ray tube

In a television system operative in trace and retrace intervals, said television system having a source of horizontal and vertical synchronization signals, a cathode ray tube having a screen, and means (21) for combining selected ones of a plurality of input signal sequences each having a predetermined variation with respect to time to create a control signal adapted to form a geometric figure at a selected location on said screen, comprising

• means (3, 12, 17) for creating said plurality of input signal sequences;
• means for inserting a DC signal into at least a selected one of said plurality of input signal sequences;
• and
• means (4) for changing the amplitude of said so-inserted DC signal until said geometric figure is at said selected location on said screen.

In a method for generating control signals for wipe transitions of video signals in the form of a geometric figure at a selectable position on the screen of a cathode ray tube, wherein the shape of said geometric figure is controlled by combination of a plurality of input signal sequences each having a predetermined variation with respect to time, said input signal sequences comprising a sequence of sawtooth signals, a process for changing said position on said screen of said geometric figure in dependence on the setting of an externally controllable adjustment element, comprising the steps of

• adding a DC voltage having an adjustable amplitude to said sequence of sawtooth signals;
• squaring said sawtooth signals with said added DC voltage, thereby creating a parabolic signal;
• constituting one of said input signal sequences;
• creating a triangular signal constituting another of said input signal sequences from said sawtooth signals with said DC voltage;
• and
• varying said amplitude of said DC voltage in dependence upon said setting of said adjustment element, whereby said position on said screen of said geometric figure changes with changes of said setting of said externally controllable adjustment element.

In a television system operative in trace and retrace intervals, said television system having a source of horizontal and vertical synchronization signals, a cathode ray tube having a screen, and means (21) for combining selected ones of a plurality of input signal sequences each having a predetermined variation with respect to time to create a wipe control signal adapted to form a desired geometric figure and to effect changes in the location of said figures on said screen, comprising

• means (3, 12, 17) for creating said plurality of input signal sequences;
• means for inserting a DC signal into at least a selected one of said plurality of input signal sequences;
• means (4) for changing the amplitude of the so-inserted DC signal to change the position of said geometric figure on said screen;
• wherein said means for creating said input signal sequences comprises means for furnishing a sawtooth signal, means for squaring said sawtooth signal thereby creating a parabolic signal, and means for creating a triangular shaped signal from said sawtooth signal, said means for creating a triangular shaped signal comprising difference amplifier means (19) having a first input for receiving a sawtooth signal, a second input for receiving a constant potential and a first and second difference amplifier output, and a mixing stage (20) having inputs connected to said difference amplifier outputs and a mixing output for furnishing said triangular shaped signal.

In a method for generating control signals for video signal wipe transitions in a television system operative at a horizontal and vertical frequency and having a cathode ray tube, wherein said wipe transition has a shape of a geometric figure movable on the screen of said cathode ray tube, and comprising the steps of

• generating a first signal sequence synchronized to said horizontal or vertical frequency;
• adding a DC signal having an adjustable amplitude to said first signal sequence, thereby creating a first input signal sequence;
• creating at least a second input signal sequence from said first input signal sequence;
• combining said first and second input signal sequence to create said control signals;
• and
• varying said amplitude of said DC signal to move said geometric figures on said screen.