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2-23
IM 704510-01E
Explanation of Functions
3
2
1
4
5
6
7
8
9
10
11
12
13
14
15
• T.(P-P/Average) (only for time variation)
Indicates the spread in the Peak-to-Peak values in terms of a percentage of the
average value.
T.(P-P/Average) =
×
100
P-P
Average
• T.RF (only for time variation)
Calculates the average value of T.(P-P/Average) of all blocks that were block
sampled.
N is the total number of blocks. P-P
k
is the Peak-to-Peak value of each block, and
AVE
k
is the average value of each block.
T.RF =
×
100
1
N
P-P
k
AVE
k
Σ
N
k=1
When in hardware histogram mode
In the equation below, n is the number of bins in the histogram. A bin of a histogram
refers to a bar (section) that indicates the frequency of occurrence on the histogram. X
i
is the median value of each bin of the histogram. Depending on the span setting of the
X-axis, the interval width of each bin becomes 25 ps in which case X
i
becomes the
measured value. For details, see “Histogram Display” on page 2-13.
• Average
Calculates the average value of the histogram. P
i
is the relative frequency*.
Average =
X
i
×
P
i
Σ
n
i=1
*
If the total number of samples on which the statistics are being calculated is N, and the
frequency of occurrence (number of samples) of a certain bin is N
i
, then the relative
frequency becomes P
i
= N
i
/N.
• Maximum
Indicates the maximum median value.
Maximum = [X
i
]
max
• Minimum
Indicates the minimum median value.
Minimum = [X
i
]
min
• Peak-Peak
Calculates the difference between the maximum and minimum values.
Peak – Peak = Maximum – Minimum
• Standard deviation (
σ
)
Calculates the standard deviation of the histogram. This indicates the degree to
which the values are spread out from the average value. P
i
is the relative frequency.
σ
=
(X
i
– Average)
2
×
P
i
Σ
n
i=1
• Flutter (
σ
/Average)
Calculates the flutter of the histogram. This indicates the spread in the values in
terms of a percentage of the average value.
σ
/Average =
×
100 (%)
σ
Average
•
σ
/T
Calculates the histogram jitter using the specified constant T. Indicates the spread of
the values in terms of a percentage of the value T.
σ
/T =
×
100 (%)
σ
T
2.7 Statistical Calculation and Inter-Symbol Interference Analysis