A Figure of Merit for Single-Pass Data Recording Systems

The problem of the interference caused by eddy current transients to the reproduction of recorded data is studied for single-pass magnetic recording systems of both the write-read and read-write variety. Signal-to-interference ratios are introduced for both modes of operation, and their variation is studied in detail. It is found convenient to introduce a dimensionless parameter a as a figure of merit for single-pass systems. This factor is a function of the velocity of the magnetic medium, the number of pulses that can be recorded per unit length, and the permeability, conductivity, and dimensions of the laminations of the recording head; it is equal to a=¿2/6Nv¿¿d2. Brief consideration is given to the effect of certain practical system factors on the conclusions reached from the theoretical analysis.