Tektronix TDSDDM1, Руководство пользователя

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Measurement Descriptions
3–24
TDSDDM1 Disk Drive Measurement Application User Manual
Figure 3–16: NLTS measurement
There is no NLTS specification in the IDEMA standard. The NLTS measurement
is based on a time domain cross-correlation method detailed in the IDEMA Test
and Measurement Committee PRML Working Group Working Paper Nonlinear
Distortion Measurement Techniques, September 1995.
NLTS Initial Magnetization.
The NLTS initial magnetization measurement assumes
the following sequence:
1. The medium is initially magnetized in one direction (DC-erased)
2. Transitions that are written by a head field in the opposite direction are
shifted later by an amount
e
0
.
The NLTS initial magnetization measurement assumes the following:
V
~
(t)
[
V
ǒ
t –
1
2
e
0
Ǔ
–
1
2
e
0
T
V
ǒ
t –
1
2
e
0
)
ǒ
M
0
–
1
2
Ǔ
T
Ǔ
Where:
V
~
(t)
is the playback voltage for a readback channel affected by
NLTS initial magnetization
V(t) is the playback voltage in the absence of nonlinear effects
Definition