A Study of the Playback Process of a Magnetic Ring Head

The playback process of a magnetic ring head with finite permeability of head and tape are studied, using the theorem of reciprocity. In order to obtain an accurate result for the playback process, the field around a magnetic gap is studied by a Fourier method. The shift of the gap null for infinite permeability of the head as calculated by Westmijze is confirmed, and the new shift is found when the tape permeability is greater than one. A simplified gap-loss function is given for the case of finite parameters for tape and head.