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 in which digital data is transmitted to store game rules, character symbology, etc. needed for the operation of a particular game. This capability would most likely be complemented with cable-generated active player symbols and backgrounds as in Category 2. above.

This is a class of CATV related games which may take the form of active participation by the home viewer in, say, a "What's My Line?" program; in scrabble-like word games originating on-stage, again with home viewer participation; and so on. The common denominator for these games is the ability to transmit digital data along with the customary visual pictorials to enter some form of viewer-owned display, such as a calculator type of readout.

Now, if you've followed me so far, you must have asked yourself whether any of these four ways of cable related electronic game areas can be accomplished with existing one-way cables, and, more importantly, with ordinary TV sets having no access to video or sync circuitry. This is the precise area we have addressed in our CATV game work at Sanders. Since some of this work has resulted in issued patents, I have no problem presenting this work here.

Let me first take a look at the technical requirements for Case No. 1, in which I used the example of TV Hockey Game superimposed on a transmitted background picture. The problem is one of obtaining horizontal and vertical sync from the received TV signal without making connections internal to the TV set. This is something we have learned to do well only recently, although practical ways of doing it are described in some of my issued patents based on disclosures I made and work done at Sanders in the sixties; secondly once vertical and horizontal sync are available and are used to phase lock the TV Game generation circuitry to establish synchronism, there remains the problem of adding the TV Game video information to that of the transmitted background picture. The solution to this problem is also described in these early patents. It involves the technique of amplitude modulating the rf signal just prior to entering the TV set antenna terminals; no new rf carrier generation is involved in this method of superimposing game video on incoming rf with composite video modulation; RFI is easily controlled and intercarrier sound operation is unimpaired.

Now let us look at the second cable games category in which I suggested, by way of an example, the transmission of prerecorded hockey player symbols along with background pictures. This is a more difficult technical problem and requires the availability of the composite video and sync signal received from the cable station by the Home Viewer's TV Set–or the availability within the viewer's game box of a separate RF front end, IF strip and video detector and sync stripper, tunable to one or two cable game channels–not too ridiculous a requirement in this day and age of linear TV IC's and surface wave bandpass

Pauline Sly listens to Dr. David Chandler describe Tank Squadron.