Characteristics of the readback signal in digital magnetic recording

A theoretical treatment for the readback process in digital magnetic recording is presented. Three major factors, namely, the medium constant
s
which defines the extent of the surface charge density, the head-to-medium spacing
d
, and the read head gap
2 g,
are taken into consideration. A general solution giving the characteristics of pulse readback signal is shown as a function of
s,d
and
g
. Both amplitude and pulse width of the readback signal are arranged as a product of the medium loss, spacing loss, and gap loss, making it easy to describe the influence of each factor separately. The final value of the amplitude and the pulse width is proportional to that of the recorded surface charge density. Spacing loss simply depends on the ratio of
d/s
; gap loss depends on the ratio of
g/(s + d)
. Theoretical results are compared with experiments which show good agreement for a wide combination of
s,d
, and
g
.