Teletype Communications at Optical Frequencies for the ALOHA System.
HAWAII UNIV HONOLULU
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The paper describes a teletype to teletype incoherent optical communications link presently operating on the campus of the University of Hawaii. A carrier on-off, direct detection communication scheme is used to transfer the binary information between teletypes. The transmission medium is the turbulent atmosphere, with emphasis on beam steering and beam spreading effects. Other types of effects, such as coherence degradation, polarization fluctuations, and beam scintillation are of no real consequence in this type of incoherent, unpolarized system. Atmospheric scattering is neglected. Receiver signal-to-noise ratio, effects of rain, and beam diameters in the transmitting and receiving planes are some of the system parameters measured and discussed. The actual light source and detector used are also discussed in some detail. The link covers about 160 yards. Author
- Non-Radio Communications