The Recording and Reproduction of Signals on Magnetic Medium Using Saturation-Type Recording

This paper discusses the various factors affecting the resolution in saturation magnetic recording. The effect on the recording process of the B-H characteristics of the coating, coating thickness, record-head gap width, head-to-coating separation, self-demagnetization, and record-head residual magnetization are discussed. Equations are derived for the playback process relating the signal amplitude and pulse width to the coating thickness, head-coating separation, and effective gap width of the playback head. It is shown that the greatest improvement in resolution can be obtained by the development of an extremely thin coating with high ratio of coercitivity to remanence and having a rectangular B-H loop. The extremely thin coating will reduce the shortcomings of the record-head field pattern, the self-demagnetization effect, and the loss of resolution in the playback process.