The author for several years has been, rather lonesomely, devoting his efforts to the development of radio as a service to the eye.
Incidentally it is suggested that there are undreamed of possibilities in radio in the unlimited frequencies above audibility, in which speed transmission is greatly accelerated by the tolerance of eyesight, not possible in an appeal to the ear. Witness, the motion picture theatre screen upon which a picture is taken off and put back again forty-eight times per second without discovery by the eye; while the slightest error in a note in the orchestra is detected at once and grates harshly on the ear.
Just as the motion picture depends for success on the fact that the eye is easily deceived, so in Radio Vision the eye is fooled into the belief that it sees the radio picture as a whole, though in fact the eye sees at any one moment only the tiny spot of light by which, with almost lightning like speed, the picture is made up.
Audio radio engineers have been working in the very limited audio-frequency band below, say, ten thousand cycles, whereas the workable range where light instead of sound is employed goes away up to millions of cycles. It is confidently predicted that the next great development in radio is in this area.
When the “teloramaphone” is made generally available, then pictures at the fireside sent from distant world points will be the daily source of news; the daily instructional class; and the evening’s entertainment; and equally the long day of the sick and shut-ins will be more endurable, and life in the far places less lonely, for the flight of radio is not hindered by rain, or storm, or snow blockades.
MECHANISMS EMPLOYED:
The successful study of the problem of the transmission of light effects electrically (vision, pictures, light signals, etc.) might well begin with the division of the subject into its elements and sub-elements.
The major division is, naturally, into (a) the sending station apparatus; and (b) the receiving station apparatus. A great variety of devices have been invented for analysis of the picture at the sending station, and the translation of the light values (which make up the picture) into electrical modulation; and likewise a variety of methods for receiving these electrical signals at a distant place (or places) and there changing the electrical modulations back into light values with which the picture is built up.
SENDING MACHINES—ZINC ETCHING:
Before the refinement of light sensitive cells, actual electrical contact was oftenest employed in sending the impulses which represented light gradations in the picture.