COAXIAL CABLE SYSTEM FOR TELEVISION TRANSMISSION 445 



Of course, actual television will not ordinarily deal with such a picture, 

 but by means of it an approximate visualization of the problem can 

 be obtained. A desired definition of 240 lines was chosen and it was 

 decided that the requirement would be to transmit square picture 

 elements as indicated in the figure. The shape of the picture which 



Fig. 7 — Photograph of the mechanical scanning disk and associated 

 experimental apparatus. 



it was convenient to use with this scanning disk is wider than it is 

 high in the ratio of 7 : 6. This differs somewhat from the standard 

 aspect ratio of 4:3, but is easily taken into account. The total 



7 

 number of picture elements in a frame is then 240^ X 7 = 67200. 



6 



