Improvements in wireless transmission and reception

Abstract

Abstract 295,957. Robinson, J. March 17, 1927 Modulating systems and apparatus.-The amplitude and mean frequency of a carrier wave are maintained constant, and the frequency is varied in accordance with the signal. The Figure shows a piezo-electric crystal Q associated with a diaphragm P<1> of a sound box or microphone M and adapted to control the frequency and to effect frequency modulation. In a modification a microphone is used and the amplified energy applied to a telephonic receiver the diaphragm of which is associated with the piezo-electric crystal. The frequency variation is preferably small and within the limits imposed by one half of the crevasse of a piezo-electric resonator and the frequency of the variation may be either sonic or supersonic. Reception is preferably effected by the supersonic method so that signals of a constant frequency may be applied to a tuned circuit shunted bv a piezo-electric crystal. Specifications 275,581 and 285,108 are referred to.

Inventors

No inventors recorded.

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