Table of Contents
Advertisement
Measurement Definition
Measurement Parameter Definition
Track Offset Compensation Function
The track offset compensation function compensates the read head position according to
the read back signal from the burst patterns. Even if the read head position drifts from the
center of the write position due to temperature changes, long period elapses and etc. this
function locates the read head at the center of write position.
NOTE
Track Offset Compensation can not be used when the system has E4402B 3GHz spectrum
analyzer.
Track Offset Compensation State
When you want to use this track offset compensation function, the function should be
turned on (hpe5022_trackOffsetCompState). In the case of ON, a track is divided into two
portions: a burst pattern area and a data pattern area.
Figure 5-28
Track Offset Compensation State
When you use gate functions in the UDS function, if the track offset function is turned on,
the gate of read/write is delayed in the period of burst pattern as if the index pulse is
located at the imaginary index position. (Figure 5-28)
The burst pattern area is used for the Track Offset Compensation function. The Track
Offset Compensation can be divided into four sequences: Calibration, Write Burst Pattern,
Read Burst Pattern, and Head Offset Compensation.
Calibration
Calibration Sequence measures the track profiles for both side tracks and determines the
PES (Position Error Signal) Line. As shown in Figure 5-29, the both side tracks' pattern
frequency and offset position are the same as a burst's pattern frequency and offset
position. The PES Line is used to find a compensation distance from a burst pattern. The
formula to calculate a PES is shown in Figure 5-29. The PES line is calculated from a PES
plot. The lead square approximation is used to find a PES line from its plot. Both the
274
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
Chapter 5
Advertisement
Table of Contents
