Inventors: David Mitchell and Robert H Nagel

US patent number:4,120,003

US patent application date: January 21, 1977
US patent issue date: October 10, 1978

SYNOPSIS OF THE INVENTION

This patent provides for a CATV type television system having a first common CATV television signal distribution means, such as the normal CATV subscriber network, to distribute a plurality of selectable video displayable television signal channels of different video information content to a plurality of subscriber normal television multichannel video display devices. This is somewhat similar to a conventional CATV television receivers, capable of receiving the plurality of channels for providing the selectable video display, and first transmitting means operatively connected to the first common CATV television signal distribution means for providing the plurality of different channels to the first common CATV television signal distribution means.

The improvement comprises a real time frame grabbing system for substantially instantaneously providing a selectable continuous video displayable frame of video information to a first video interface means, such as a row grabbing terminal, having a preselected frame address, for providing a preselected continuous video displayable frame of such information to at least one of the channels as the video information content thereof from continuously transmittable information.

The real time frame grabbing system comprises second means for transmitting the video information as a plurality of pseudo video scan lines with each of the pseudo video scan lines having a television video scan line format and capable of comprising a complete self-contained packet of digital information sufficient to provide an entire displayable row of video data characters.

The pseudo video scan line has an associated transmission time equivalent to that of a television video scan line and the packet of digital information comprises at least address information for the displayable row and data information for the displayable characters in the displayable row with the pseudo video scan line signal being a composite video signal. The real time frame grabbing system further comprises second television signal distribution means for distributing the transmitted composite pseudo video scan line signals to the first video interface means for providing the preselected frame of video information to the one channel with the first video interface means forming a portion of the aforementioned first transmitting means.

The first video interface means is operatively connected between the second television signal distribution means and the first common CATV television signal distribution means for processing the distributed composite pseudo video scan line signals for providing a video displayable row from each of the pseudo video scan line signals pertaining to the preselected frame for providing a selected continuous video displayable frame of dedicated information to the one channel.

A predetermined plurality of such displayable video rows comprises a displayable video frame of information. In this manner, a plurality of CATV subscribers may receive a dedicated common channel of preselected frame grabbable information on a normal television signal channel over the CATV television signal distribution network.