Optical Recording (I)

Optical Recording (I) A system of recording sound on film through a photographic process. The sound signal activates a light valve, causing variations in the light that falls upon and exposes the film as it moves past the valve. The changes in density that result are analogs to the frequency and amplitude of the original signal. Playback is achieved by drawing the film between a photoelectric cell and a light source, producing a fluctuation that is converted back into sound. Because the…