On digital recording head design

Hand and computer methods are presented for calculating sensitivity figures of recording heads. Given a two-dimensional core configuration, the permeabilities of the core materials, the coil location, and the location of the gap(s), the head sensitivity may be computed in oersteds within the gap per ampere-turn of drive. The effects of field dependent permeability and leakage flux are included in the calculation. Experimental sensitivities measured from readback amplitudes from a digital disk file head match the calculated sensitivity to within 15 percent. Sensitivity figures may be used to determine the recording field intensity and the readback pulse, and may be related to inductance and to the electromagnetic uniformity of the head under dimensional and magnetic tolerances.