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Measurement Definition
Parametric Sweep Measurement Definitions
width and the track center, as shown in Figure 5-38. The track center is defined as the
position of the head during write sequence.
Figure 5-39
Track Geometry
General Definition of Track Geometry is as follows:
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Micro Track Profile Measurement
For diagnostics of read/write operations it is often useful to plot the track profile measured
by a very narrow read element. This test serves as a diagnostic tool in determining the
effect of fringing fields in the read signal. Ideally, the Micro Track Profile will have a sharp
apex at the center when the head is at the center of the written track. If the apex is rounded,
it indicates that fringe signal is being pick-up by the read head.
Using Micro Track Profile in Measuring the Read Head Width.
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Track Pitch is defined as the distance between the centers of two adjacent tracks.
Erase Band (e) is defined as the magnetic pattern created by the fringe field whose
magnetic orientation is different from the written data pattern created by the write head.
It protects the test track from picking up other signals from its neighboring tracks, i.e.,
intersymbol interference or ISI from adjacent track.
Guard Band acts to separate two adjacent tracks in order to avoid track misregistration.
Ideally its length extends between centers two erase bands of two adjacent tracks.
Write Width is defined as the width of the written track plus 50 percent of the erase
band. As data is written along the track, the write head produces a fringe field that
re-magnetizes the media on each side of the track. However this field has a different
magnetic orientation and gradient such that it shouldn't interfere with the read signal
output. The fringe field is an inherent characteristic of the write head due to the head's
construction.
Read Width is defined as the width of the read head.
Chapter 5
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