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...Atmospheric conditions depending on their wavelengths these electromagnetic carriers can be transmitted over considerable distances but are limited in the amount of information they convey by frequencies i e carrying capacity is directly related to bandwidth or frequency extent modulated carrier which generally a fixed fraction theory greater larger available transmission and thus communication system for this reason radio was developed higher vhf uhf leading introduction even microwave latterly millimeter wave relative types observed from spectrum shown figure context it may also noted that at optical offers an increase potential usable factor around high additional benefit use general ability concentrate power within giving improved performance renewed interest stimulated early s with invention laser device provided powerful coherent light source together possibility modulation addition low beam divergence made enhanced free space practical however previously mentioned constraints at...