The readback process in digital magnetic recording

Losses in analog magnetic recording can be separated and analyzed by frequency response techniques. In digital recording these cannot readily be applied but, as this paper shows, useful results can be obtained from a time domain analysis of the readback process. The commonly accepted model of this process as a convolution of the media magnetization transition and the head field function is extended by the use of linear theory to include the electrical parameters of the head amplifier system. The resulting model is then analyzed to show how the three contributions to the readback process -the written transition, the head field, and electrical effects-might be separated by suitable experimental techniques. Electrical effects are readily separable and experimental results agree well both with the theory and with established head parameters. The separation of reading and writing effects is shown to be difficult to achieve under conditions likely to be encountered in practice, but an approximate method is discussed.