METHOD AND APPARATUS FOR TELEMETERING BY MEANS UTILIZING MODULATED LIGHT BEAMS

摘要

A method and arrangement for transmission and electronic evaluation of a modulated light beam used for telemetry in which the modulation signal appears as an argument of a sinusoidal function. The modulated sinusoidal function is transformed into two parallel signals phase-shifted by pi /2 which are subsequently converted at a receiving station into two correspondingly phase-displaced electrical signals. The electrical signals are then mixed multiplicatively with sinusoidal signals phase displaced by pi /2 having a fixed angular frequency, the products resulting from the multiplicative mixing are added, and the latter are then frequency-demodulated.