A computer simulation of unbiased sine wave recording

A computer simulation is described which uses the approximation that the output voltage derives from longitudinal tape magnetization acquired solely from the longitudinal head field. Using a simple noninteracting
M_{r}-H
model, the remanent state of 200 points per half-wavelength of tape is calculated by following each point's field history as it passes the record head. We discuss the amplitude and phase angle of the magnetization sinusoids obtained by harmonic analysis. At short wavelengths (wavelength less than coating thickness) we find, for regular γ-Fe
2
O
3
tape, that although the peak output is limited by record head field gradient effects, the over-recording phenomenon is attributable to the field shape. The process of "optimizing" the record current is thus shown to be explicable in terms of the record head field geometry. These conclusions hold equally for "partial penetration" recording of high density digital waveforms.