Chapter 5
261
Measurement Definition
Measurement Parameter Definition
1.
Ch
apt
er
T
itl
e
2
. Cha
p
te
r T
itle
3
. Chap
te
r T
itle
4
. Chap
te
r T
itl
e
M
e
as
ur
em
e
n
t
De
finit
ion
Equation 5-20
Correlation Calculation Formula
Signal to Noise Ratio (SNR)
SNR is the measurement ratio between the peak to peak TAA signal and the noise signal
measured in ‘rms’ from an erased track. The measurement is performed by the parametric
module.
Equation 5-21
SNR
SNR is measured from the equation given above, where
Equation 5-22
Crest Factor
V
ppTAA
defined as the peak to peak voltage of the TAA. V
MaxNoise
is defined as the
maximum voltage for one revolution of the erased track.
r V t
( )
V t
NT
+
(
)
[
,
]
1
NT
-------
V t
( )
V t
NT
+
(
)
t
d
0
NT
∫
V t
( )
V t
NT
+
(
)
Ð
V t
( )
2
V t
( )
(
)
2
Ð
[
]
V t
NT
+
(
)
2
V t
NT
+
(
)
(
)
2
Ð
[
]
Þ
----------------------------------------------------------------------------------------------------------------------------
=
V t
( )
1
NT
-------
V t
( )
t
d
0
NT
∫
=
V t
( )
2
1
NT
-------
V t
( )
2
t
d
0
NT
∫
=
SNR
20
V
ppTAA
V
rmsNoise
----------------------
log
=
CrestFactor
V
MaxNoise
V
ppTAA
------------------------
=
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