Bell telephone magazine (1922) (14569377498)

Identifier: bellvol25telephonemag00amerrich (find matches)

Title: Bell telephone magazine

Year: 1922 (1920s)

Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept

Subjects: Telephone

Publisher: (New York, American Telephone and Telegraph Co., etc.)

Contributing Library: Prelinger Library

Digitizing Sponsor: Internet Archive

Text Appearing Before Image:

gathered, their suc-cessors began to think along the samelines. When the Laboratories en-tered the SONAR program, the great-est need was for precise methods ofmeasuring underwater sound, a fieldin which little quantitative work hadbeen done. Yet this was an impor-tant aspect, for precise measurementis a fundamental factor in good de-velopment and design of any equip-ment. With their broad experience in the measurement of ordinary soundin the development of telephony. Lab-oratories engineers undertook investi-gations which laid the groundworkfor the standardization and improve-ment of sonar techniques. In 1941 and 1942 they establishedthe first lake calibration stations, onein New Jersey and the other in Flor-ida. These were later taken over bythe National Defense Research Com-mittee as the national standardizinglaboratories for underwater sound. Sonar locates hostile submarinesby projecting a beam of vibrationsthrough the water and observing the Bell Laboratories^ Role in Victory 117

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Above: the Elcovee,^^ a floatinglaboratory used in the develop-ment of sonar Right: How the sonar antennais lowered and retracted CROSSSECTfON 01= 5MIP time and direction of the echo. Theprinciple is the same as that of radarbut the vibrations are of water mole-cules, and the frequencies are meas-ured In tens of thousands Instead ofmillions. Most difficult part of thejob was to devise a transducer, a de-vice to convert electrical vibrations tomechanical and vice versa. The Lab-oratories developed a synthetic piezo-electric crystal for this, and withWestern Electric worked out a pro-cedure to make it In very large quan-tities. Another contribution was a dometo be attached to the ships hull tohouse the transducer. Its stream-lining and other features minimizednoise pick-up—a very important fac-tor. About three-score differenttransducers were designed for spe-cial uses. Equally important was the Lab-oratories contribution in the formof good design of the sonar circuits,which generated

bell telephone magazine 1946 book illustrations electric power history of technology new jersey bell telephone company telephone american telephone and telegraph company telephony images from internet archive

1922

New Jersey State Library

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