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Interactive Selective Blanked Video Display

IP.com Disclosure Number: IPCOM000076578D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 34K

Publishing Venue

IBM

Related People

Featherston, JR: AUTHOR [+2]

Abstract

Effective viewer interaction with a standard TV receiver video display is provided by division of the visible area of the cathode-ray tube (CRT) receiver into a number of sections, which can be blanked or displayed under relatively simple logical circuitry control in accordance with the viewers response.

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Interactive Selective Blanked Video Display

Effective viewer interaction with a standard TV receiver video display is provided by division of the visible area of the cathode-ray tube (CRT) receiver into a number of sections, which can be blanked or displayed under relatively simple logical circuitry control in accordance with the viewers response.

As one example, in an educational application the screen is divided into eight horizontal bars or stripes. The upper four stripes (top half of the screen) are used to display a problem, including a multiple choice of four solutions. Initially, the lower four stripes are blanked (not displayed). The student chooses one of the displayed solutions of the problem and enters his choice by manipulating a keyboard or probe, actuated by light from the CRT electron beam impinging on the phosphor screen. Any one of the four responses will unblank a corresponding stripe in the lower half of the screen. The stripe then displayed contains the appropriate comment on the learner's response.

A time base can be readily generated which further divides the visible area into equal subdivisions or sections in the horizontal dimension. This can be combined with the blanking gate derived above to permit selective blanking of subportions of a television line. In the first mode described above, this would give eight response fields on the lower half of the picture, if for example, the line were divided in half.

A composite video signal applied at input terminals 10 is gated in AND gating circuit 14 for delivery at output terminals 20. Horizontal and vertical synchronizing pulses are extracted from the composite video signal delivered to terminals 22 by a conventional synchronizing pulse separating circuit 24. The vertical sync pulse triggers a bistable circuit 26 which conditions AND gating circuit 28, allowing the horizontal pulses to drive a divide by 16 counter 30. The carry output of counter 30 drives a second divide by 16 counter 32. When a carry occurs from the second counter, the trigger 26 is turned off preventing further counts and leaving counters 30 and 32 in a known all-zero condition.

The carry pulses of the first counter 30 are us...