User guide

Eye Measurements - Reference
Eye results are displayed for the Current Align and Previous Align process. They
are also graphically displayed on a representation of an eye diagram.
Eye Width and Height
Eye width is the inside horizontal opening of the data eye in an eye diagram. This
measurement is made by the error detector after an Auto Align or Data Center.
The eye width at the current 0/1 decision threshold is displayed on a simulated
eye diagram. The left and right eye edges are determined by the user-defined BER
threshold. Different BER thresholds will produce different eye width results.
Eye
width
Left eye
edge
Right eye
edge
Eye height is the inside vertical opening of a data eye in an eye diagram. This
measurement is made by the error detector after an auto align or 0/1 threshold
center. The eye height at the current data input delay point is displayed on a
simulated eye diagram. The upper and lower eye edges are determined by the user-
defined BER threshold. Different BER thresholds will produce different eye height
results.
Eye height
Upper eye
edge
Lower eye
edge
Evaluating Results 7
Agilent J-BERT N4903B High-Performance Serial BERT 393