Teledyne LeCroy AORM - Advanced Optical Recording Measurements - Manual (Page 55)

AORM Software Package
923133 Rev A ISSUED: June 2013
53
DISPLAY TYPE VALUE DISPLAYED
Parameter Statistics Off
All values of the overall edge shift for all pits/spaces within the
selected ‘nT’ range for last acquisition.
Parameter Statistics On
Average, minimum, maximum, and sigma of all edge shift
values calculated per acquisition for all acquisitions since the
last C
LEAR S WEEPS operation.
nT Table
List of values of the overall edge shift for each group of
pits/spaces of common ‘nT’ width for the last acquisition.
Histogram Function
Histogram of the single overall edge shift value calculated for
each acquisition for all acquisitions since the last C
LEAR S WEEPS
operation.
Trend Function
Trend of the single overall Edge Shift value calculated for each
acquisition for all acquisitions since the last C
LEAR S WEEPS
operation.
Example
The example shows the CD data signal measured at the selected voltage threshold containing, in
sequence, a 5T pit, 3T space, 3T pit and 4T space. If the clock period ‘T’ is 231.5 ns, then the 5T
and 4T edge shift value is simply the difference between the width calculated and the ideal width
(since there is only one pit/space of that ‘nT’ width), thus:
( )
( )
edgsh T
edgsh T
( ) .
.
.
( ) .
.
.
4 920 4 2315
100%
2315
2 59%
5 1160 5 2315
100%
2315
1 08%
= − ⋅ ⋅ = −
= − ⋅ ⋅ = +
The 3T edge shift value is the average difference:
( ) ( )
edgsh T ( )
.
.
.
.
. 3
690 3 2315
100%
2315
695 3 2315
100%
2315
2
0 86%
=
− ⋅ ⋅
⎛
⎝⎜
⎞
⎠⎟ +
− ⋅ ⋅
⎛
⎝⎜
⎞
⎠⎟
= +
In an nT Table display, these three values would be shown in the appropriate nT location.