User guide

The Sample Point in the eye diagram moves horizontally as you change the
value.
T I P
While adjusting the data input delay, you can monitor the BER bar on the analyzer
display, or listen to the BER warning tones. Higher BERs may indicate that you are
measuring at the edges of the data eye.
N O T E
Pattern synchronization can be lost during sampling point adjustment. If Auto
Sync is enabled, the Serial BERT will resynchronize the patterns automatically. If
the manual synchronization mode is selected, you need to synchronize the error
detector by clicking the Pattern Sync icon and then the Sync Now button.
How to Adjust the 0/1 Decision Threshold
1
Click Sampling Point Setup menu item from the ED Setup submenu.
2
Clear the Avg. 0/1 Threshold checkbox.
3
Click 0/1 Threshold Center to move the sampling point vertically towards the
center of the eye at the selected delay. You may click Cancel at any time.
4
Now you can use the numeric keypad or front panel knob to manually adjust
the value in the 0/1 Threshold field.
The Sample Point in the eye diagram moves vertically as you change the value.
T I P
While adjusting the 0/1 threshold, you can monitor the BER bar on the analyzer
display, or listen to the BER warning tones. Higher BERs may indicate that you are
measuring at the edges of the data eye.
N O T E
Pattern synchronization can be lost during sampling point adjustment. If Auto
Sync is enabled, the Serial BERT will resynchronize the patterns automatically. If
the manual synchronization mode is selected, you need to synchronize the error
detector by clicking the Pattern Sync icon and then the Sync Now button.
How to Enable the Bit Recovery Mode
The bit recovery mode (BRM) allows you to measure the relative BER without
knowing the incoming data pattern.
To enable the bit recovery mode:
1
Click Sampling Point Setup menu item from the ED Setup submenu.
Setting up the Error Detector 5
Agilent J-BERT N4903B High-Performance Serial BERT 197