The Bell System Technical Journal 



October, 1927 

 Television ^ 



By HERBERT E. IVES 



Synopsis: The chief problems presented in the accomplishment of 

 television are discussed. These are: the resolution of the scene into a series 

 of electrical signals of adequate intensity for transmission; the provision of 

 a transmission channel capable of transmitting a wide band of frequencies 

 without distortion; means for utilizing the transmitted signals to re-create 

 the image in a form suitable for viewing by one or more observers; arrange- 

 ments for the accurate synchronization of the apparatus at the two ends 

 of the transmission channel. 



Introduction 



THIS paper is to serve as an introduction to the group of papers 

 following, which describe the apparatus and methods used in 

 the recent experimental demonstration of television over communi- 

 cation channels of the Bell System. In that demonstration television 

 was shown both by wire and by radio. The wire demonstration 

 consisted in the transmission of images from Washington, D. C, to 

 the auditorium of the Bell Telephone Laboratories in New York, a 

 distance of over 250 miles by wire. In the radio demonstration, 

 images were transmitted from the Bell Laboratories experimental 

 station at Whippany, New Jersey, to New York City, a distance of 

 22 miles. Reception was by two forms of apparatus. In one, a 

 small image approximately 2 in. by 23^ in. was produced, suitable 

 for viewing by a single person, in the other a large image, approxi- 

 mately 2 ft. by 23^2 ft., was produced, for viewing by an audience of 

 considerable size. The smaller form of apparatus was primarily 

 intended as an adjunct to the telephone, and by its means individuals 

 in New York were enabled to see their friends in Washington with 

 whom they carried on telephone conversations. The larger form of 

 receiving apparatus was designed to serve as a visual adjunct to a 

 public address system. Images of speakers in Washington addressing 

 remarks intended for an entire audience, and of singers and other 

 entertainers at Whippany, were seen by its use, simultaneously with 

 the reproduction of their voices by loud speaking equipment. 



'Presented at the Summer Convention of the A. I. E. E., Detroit, Mich., June 

 20-24, 1927. 



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