Record carrier for electrical or mechanical oscillations - is gramophone record disc made by pressing plastics material with track made of magnetic oxides

摘要

The upper surface of the record carrier has a zone in which the oscillations are recorded as ridges in the carrier surface, and a further zone with a smooth surface for a magnetic recording, on the same side of the carrier. The recording heads for the two zones are mechanically coupled together, so that the distance between the two recordings remains fixed and on playback the grooves act as guides for the correct positioning of the magnetic playback head. The link connecting the stylus and the magnetic head lies along a radius of the disc.