Method of coding magnetic tape

摘要

A description is given of a method of applying additional information to supplement audio and/or video recordings on magnetic tape, this additional information being applied on the control track and characterised in that the pulse length ratio of the positive and negative signal trains of the synchronising pulse is changed. In this way, characteristic data important for a duplicating company can be applied to the magnetic tape. Furthermore, the method according to the invention allows an original to be distinguished from an illegally produced copy.