Abstract :
When a tape is passing a reproduce head, the reversa of direction of the remanent magnetization induces a pulse in the head coil. In the most widely used NRZ technique, the recorded digital information is composed of a number of such pulses. In order to derive an expression for the output of a reproduce head by a finite medium thickness, we must know the profile of the reversal of magnetization throughout the oxide thickness. Tjaden and Leyten have analyzed this profile with a tape-head model with the scale 5000 to 1. If, for measurement, the total thickness is divided into several laminas by using a thin coated tape which is spaced varying distances away from the head, a comparable curve is obtained for the location of the flux reversal inside the coating. This measurement can be done under the actual dimensions of a regular tape. It can be shown, that this curve is allowed to be approximated by a straight line. Furthermore we may assume, that the value of magnetization inside the coating depth is constant. Now we can establish a general expression for the output pulse as a function of the gap length, the coating thickness, the spacing tape-head, and a suitable parameter for the slope of the magnetization profile. The next step to a complete computation is the inclusion of the reproducing head transient function.
