A computer simulation of unbiased digital recording

This simulation is intended for use at low, intermediate, and high bit densities. While simpler algorithms can be found for use with either very low bit densities only, or with very high bit densities only, they lack the generality needed for this purpose. The simulation is composed of three distinct sequential computations. First, using a noninteracting particle idealized
M_{r}-H
model and the arctangent head field formula, the tape magnetization is computed at 40 points per bit length in each of 5 laminae. Second, this magnetization is averaged throughout the tape thickness and harmonically analyzed. Finally, each harmonic component is weighted according to a demagnetizing-remagnetizing factor given previously, and the final output voltage waveform is computed. Linearity and superposition are thus assumed for all processes following the obviously nonlinear record mechanism. Computed outputs are compared with experimental results for both single transition and multiple transition inputs. The widths of computed and measured isolated output pulses differ by no more than 10 percent, without the adoption of physically unreasonable parameters. Output signals were computed for multiple transition inputs up to 20 000 flux reversals per inch (fr/in), and these compare well with experimental results up to 15000 fr/in.