TECHNES Encyclopedia Database

This system, in use from 1954, which required a cable between the two devices, was improved with the pilot tone (or pilottone),^[4] which spread with the introduction of the Nagra III. This was the first example of a servo control system. The pilot tone sends a pilot frequency, meaning a sinusoidal oscillation, which gives information about its speed. This signal, recorded on an auxiliary track of the magnetic tape, makes it possible when rerecording in post-production to synchronise sound and image. The sound recordist and the camera operator nevertheless remained “bound” by this cable.