Teledyne LeCroy SDA III-CompleteLinQ - Manual (Page 20)

SDAIII-CompleteLinQ Software
or other small glitches in the signal. The default value is 500mdiv, or 1/2 a division. When the input sig-
nals are properly scaled (i.e. to fill approximately 90% of the grid, vertically, this level of hysteresis should
be sufficient. When dealing with signals that result in closed eyes, a smaller value for hystersis may be
required.
More information about how the SDA analysis software determines the edge timing using the crossing
level can be found in the
Clock Recovery Theory section
NOTE: The Relative setting can potentially remove jitter by tracking slow level shifts between acqui-
sitions, if this is not desired, use the Absolute level setting.
Signal Types
The signal type defines the compliance masks and bit rate for the selected standard.
When you touch the Signal Type field, a pop-up table of standard signal types is shown. Touch the
desired signal type to populate the Signal Type field. The list of signal types is taken from the SDA Mask
Database. As new serial data standards are invented, masks are added to the database.
The Nominal Rate entry box in the Signal dialog is automatically populated when selecting a signal type
other than custom.
When choosing Custom from the Signal Type pop-up menu, always enter a bit rate in the Nominal Rate
entry box. Using an incorrect Nominal Rate can lead to incorrect equalizer results, since this value is used
by several of the equalizers that are available the oscilloscope includes Eye Doctor II functionality. The
Custom selection does not specify any eye masks, and the Mask Type selector in the Eye dialog will be
greyed out.
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