COMPUTATION OF MAGNETIC-FIELDS FROM RECORDING SURFACES WITH MULTIPLE TRACKS

Calculations of the magnetic fields emanating from a recorded surface that contains an infinite number of identical tracks are presented. Th e solutions are obtained by assuming that the magnetization is uniform through the thickness of the film and can be represented by Fourier s eries in the other two dimensions. Solutions are obtained for both lon gitudinal and vertical recording. To make these calculations useful Fo urier distributions are obtained with arctan transitions that are both representative and easy to use. These magnetic fields are then used t o calculate the voltage from an idealized reproduce head. Effects on t he output voltage caused by track width, track separation, head regist ration, and transition lengths can then be calculated. Examples are gi ven and it is shown that the effects can be large, compared to the usu al infinite track width calculations, when the track width or the trac k separation become comparable to the recorded wavelength.