LeCroy DDA 7 Zi series, Operator'S Manual

Page: 323 / 544

Operator's Manual
WP700Zi-OM-E-RevA
322
The measurement calculation is compliant with the definition of Timing Jitter as defined by ISO/IEC
JTC1.23.14517 Section 22.4.
Display Options
ORM parameter calculations can be displayed, histogrammed, and trended in a variety of ways. This table
provides a concise description of the value or values displayed using each approach.
DISPLAY TYPE VALUE DISPLAYED
Parameter
Statistics Off
Single value of the overall timing jitter for pits/spaces of interest for last acquisition.
Parameter
Statistics On Average, minimum, maximum, and sigma of the overall timing jitter value calculated per
acquisition for all acquisitions since the last CLEAR SWEEPS operation.
nT Table
List of values of the timing jitter for each individual ‘nT’ in the selected range of ‘nT’ for the
last acquisition.
Histogram
Function
Histogram of the overall timing jitter values calculated for each acquisition for all
acquisitions since the last CLEAR SWEEPS operation.
Trend Function
Trend of the overall timing jitter values calculated for each acquisition for all acquisitions
since the last CLEAR SWEEPS operation.
Example
A waveform is acquired with 3T, 4T, and 5T pit widths as follows:
3T 4T 5T
695 ns 925 ns 1.16
P
s
690 ns
1.18
P
s
696 ns
T is 231.5 ns, and the timing jitter parameter has been configured for a range of 3T through 5T.
The 3T mean is 693.66 ns. The 4T mean is 925 ns. The 5T mean is 1.17
P
s.
The 3T timing jitter is calculated by taking the standard deviation of the difference between each width and the 3T
mean. This is 3.214 ns, normalized by:
The 4T timing jitter cannot be calculated because there is only one value (at least two values are required).
The 5T timing jitter is +6.109%.
The overall timing jitter is calculated using a weighting formula, which results in the standard deviation of the
mean centered distributions. In this example, it is calculated as: