. The Bell System technical journal . s ap-pear. The disk rotates inside of a rectangu-lar cabinet and the observer views the imagethrough the shielding window. The largestdisk, three feet in diameter, gives a 2 in. by2]^ in. rectangular image. Each televisionreceiver is also equipped with a telephone re-ceiver and transmitter; and it is possible for the observer to both see and converse with a distant person at the same time. Fig. 7—Neon receivinglamp. The rectangularcathode is covered by auniform layer of glowslightly larger than thefield of view on a televi-sion disk PRODUCTION OF TELEVISIO
. The Bell System technical journal . s ap-pear. The disk rotates inside of a rectangu-lar cabinet and the observer views the imagethrough the shielding window. The largestdisk, three feet in diameter, gives a 2 in. by2]^ in. rectangular image. Each televisionreceiver is also equipped with a telephone re-ceiver and transmitter; and it is possible for the observer to both see and converse with a distant person at the same time. Fig. 7—Neon receivinglamp. The rectangularcathode is covered by auniform layer of glowslightly larger than thefield of view on a televi-sion disk PRODUCTION OF TELEVISION SIGNALS 569 Considering the limited number of picture elements, a surprisingamount of detail can be transmitted with this television system. Adistant person can be seen and easily recognized and his motions canbe plainly followed as he talks into a transmitter, turns the pagesof a magazine and goes through other similar motions. Large-sizedpictures in a magazine can be seen as the subject turns the pages andlooks at them Fig. 8—Disk receiving apparatus. The observer looks through the shielding windowat a picture on the 36-inch disk An auxiliary television receiving system also accompanies eachtransmitting set and enables the operator to see that he is sending asatisfactory picture current out over the channel of auxiliary or pilot picture is formed on the scanning disk small fraction of the outgoing picture current is tapped off andamplified to operate a neon lamp, which is placed behind the diskninety degrees around from the scanning beam. An image of thesubject may thus be seen on the scanning disk just as at a receiving 570 BELL SYSTEM TECHNICAL JOURNAL Station. To correct for the ninety-degree phase shift, the spiral ofapertures on the transmitting disk is continued by additional aperturesa quarter of a turn beyond the starting point. The first turn aloneof the spiral is used for scanning; and the last turn alone, to form thepilot
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
