. Bell telephone magazine . r hcani sent throiii^h dtnios-phere: star-like pattern is caused when hii>hl\-directional beam hits edi^es of camera iris. and snow, it often exceeds 80 db. Therefore,optical communication systems may requirethat the light beam be transmitted in under-ground pipestoshield this experiment, a ten milliwatt helium-neon optical maser generates a continuousbeam with a wavelength of microns. Thebeam is vertically polarized and sent through3 nine-cm-diameter telescope. After passingthrough the atmosphere it is received by arefracting telescop
. Bell telephone magazine . r hcani sent throiii^h dtnios-phere: star-like pattern is caused when hii>hl\-directional beam hits edi^es of camera iris. and snow, it often exceeds 80 db. Therefore,optical communication systems may requirethat the light beam be transmitted in under-ground pipestoshield this experiment, a ten milliwatt helium-neon optical maser generates a continuousbeam with a wavelength of microns. Thebeam is vertically polarized and sent through3 nine-cm-diameter telescope. After passingthrough the atmosphere it is received by arefracting telescope (with filters, polarizers,and attenuators) and fed toa photomultiplier. Microwave Watchdog m A complex emergency switching sys-tem that functions in millionths of asecond is giving unprecedented life insur-ance to long distance communications. By• automatically routing calls to standby cir-:uits, the system rescues radio relay sta- ;//(// adjnstnients I or one of hays of eqiiip-neni in 100A Protection Switchinii tions whenever transmission quality onnormal channels falls below par. This new electronic watchdog, consistingof six bays of switching and power equipmentmanufactured by Western Electric, is calledthe lOOA Protection Switching System. Itsjob is to stand ready at microwave stationsthat amplify and pass on telephone, televi-sion and data transmissions and to protectagainst service interruptions caused by fad-ing signals or equipment failure. Protection switches for microwave sys-tems are nothing new, but the lOOA wasdeveloped by engineers at Bell Laboratoriesspecifically to handle the growing speed andvolume of long distance microwave trans-missions. This first all-electronic protectionsystem works 100 times faster than the fast-est previous switch, enabling it to keep paceinstantly with even the most rapid datacommunications. Electronic Clock ■ A complex clock that in all probabilitywill not lose or gain more than a sec-ond in 300 years helps Western Elec
Size: 1561px × 1601px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthoramerican, bookcentury1900, bookdecade1920, bookyear1922
