Magnetic recording in film production

A very high standard of recorded quality can only be obtained by attention to details of mechanical and electronic design which are common to magnetic recorders irrespective of a particular application. Additionally, there are two fundamental requirements for the adaptation of magnetic recorders for sound films: the sound record must at all times be held in accurate synchronism with the associated picture and yet, at the same time, it must be physically separate to permit editing. The paper describes an equipment for this purpose which makes use of a twin-channel magnetic tape carrying synchronizing signals. The synchronizing signal, lying between 1000 and 5000 c/s, is pulse modulated at picture frequency or a multiple thereof (24 or 48 c/s).