Teledyne LeCroy AORM - Advanced Optical Recording Measurements - Manual (Page 41)

AORM Software Package
923133 Rev A ISSUED: June 2013
39
EES ENDING EDGE SHIFT
Description
EES provides a measurement of the time between the ending edge of the subject n in a specified
space/pit pair and the nearest specified clock edge. The measurement is calculated between the
points where the data and clock signals cross selected voltage thresholds. The clock period T can
be entered by the user or measured from a user supplied clock signal, as described below.
The value calculated depends on the clock and data edges selected, as shown in the table below.
The Data Slope menu selects the polarity of the subject n pit/space. If Pos (positive) is selected,
the measurement is performed from the ending edges of positive polarity pits and categorized by
the following space. If Neg (negative) is selected, the measurement is performed from the ending
edges of negative polarity spaces and categorized by the following pit. If Both is selected, the
ending edges of both pits and spaces are used in the calculation and categorized by the following
inverse polarity space/pit. The sizes of pits or spaces used in the measurement are also
determined by the range of ‘nT’ values chosen.
DATA SLOPE
CLOCK
EDGE
Pos Neg Both
Positive time between ending
edge of positive polarity
subject pit and nearest
positive clock edge time between ending
edge of negative
polarity subject space
and nearest positive
clock edge time between ending
edge of subject pits and
spaces to nearest
positive clock edge
Negative time between ending
edge of positive polarity
subject pit and nearest
negative clock edge time between ending
edge of negative
polarity subject space
and nearest negative
clock edge time between ending
edge of subject pits and
spaces to nearest
negative clock edge
Near time between ending
edge of positive polarity
subject pit and nearest
clock edge time between ending
edge of negative
polarity subject space
and nearest clock edge time between ending
edge of subject pits and
spaces and nearest
clock edge
The next figure demonstrates the measurement of the ending edge shift on a single subject 4T pit
followed by a 3T space. In this example, the clock is specified as the positive edge. For each pit/space
combination, the ending edge shift is calculated as the time difference between the ending pit edge and
the clock edge. Additionally, the measurements will be sorted by the pit/space pairs. For the positive
polarity pit example shown in the figure after next, the measurements t+, and t- are for a single ending edge
shift measurement configured for positive edge, or negative edge. If nearest is selected the smaller of t- or t+
is used.