If the R
2
value falls below 0.75, the Q-factor calculations are not
applicable.
•
Q Low Level
The Q Low Level is the mean, calculated from the linear regression
curve for the low level data:
m
=
-A
B
•
Q Low Level Std.Dev
The Q Low Level Standard Deviation is the
σ
(Sigma), calculated
from the linear regression curve for the low level data:
s
= -
1
B
•
Q Low Level Nr. Points
This is the number of data points used for the calculation of the Q
Low Level value. It depends on the setting of the
BER Threshold
and
also on the setting of the
Min BER for Q
parameter.
The minimum for calculating Q-factor values is two points. It is
recommended to include more than 5 points.
•
Q Low Level R^2
See the definition of "Q High Level R^2".
Unavailable Values
Under certain circumstances, some numerical results are not available.
This is indicated by
<invalid>
or
<not applicable>
in the numerical results
table below the measurement graphic.
•
<invalid>
indicates that the value could not be calculated. This is the
case, for example, for phase margin, when the BER threshold is set
to high values and does not intersect with the bathtub curve.
•
<not applicable>
indicates that the value could be calculated, however
is not shown because quality criteria are not met. This is the case,
for example, for RJ/DJ results, when the r^2 value of one or both
edges is <0.75. Even though RJ/DJ values can be calculated in this
case, they are not shown because confidence in the results is too low.
Advanced Analysis
5
Agilent J-BERT N4903 High-Performance Serial BERT
215
Summary of Contents for J-BERT N4903
Page 1: ...S Agilent J BERT N4903 High Performance Serial BERT User Guide s Agilent Technologies...
Page 68: ...2 Setting up Patterns 68 Agilent J BERT N4903 High Performance Serial BERT...
Page 158: ...4 Setting up the Error Detector 158 Agilent J BERT N4903 High Performance Serial BERT...
Page 314: ...6 Evaluating Results 314 Agilent J BERT N4903 High Performance Serial BERT...
Page 374: ...7 Jitter Tolerance Tests 374 Agilent J BERT N4903 High Performance Serial BERT...
Page 394: ...8 Solving Problems 394 Agilent J BERT N4903 High Performance Serial BERT...
Page 434: ...Index 434 Agilent J BERT N4903 High Performance Serial BERT...
