Tektronix TDSDDM1, Руководство пользователя

Страница: 65 / 102

Measurement Descriptions
TDSDDM1 Disk Drive Measurement Application User Manual
3–23
Nonlinear Transition Shift, NLTS
The nonlinear transition shift measurement, NLTS, measures three types of
nonlinear transition shift on the media:
H
Initial magnetization (DC erased)
H
First adjacent transition
H
Second adjacent transition
The initial magnetization of the media can affect the position at which transitions
(reverses in magnetization) are recorded. Initial magnetization is characterized by
a delay in a transition, occurring when the new transition reverses the direction
of the previous magnetization.
The second transition in a series of consecutive transitions is called the adjacent
transition, or first adjacent transition. The first adjacent transition is characterized
as follows: when write data requires transitions on consecutive data bits, the
latter transition is shifted earlier in time. In other words, when one transition in a
series occurs, then the following transition occurs earlier than it should.
All subsequent transitions in the series of consecutive transitions are grouped
into the category called second adjacent transition. Second adjacent transitions
are similar to first adjacent transitions. The difference is that the transitions are
separated by two bit periods, not one.
When nonlinear transition shift can be characterized, its behavior can be
mitigated with write pre-compensation.