Agilent Technologies J-BERT N4903B, User Manual, Page: 522 / 572

If you cannot see a clear eye diagram, then check if the M8061A is connected
properly to the J-BERT N4903B. The M8061A must be connected to Aux Data Out,
Data Out and Aux Clk Out to work properly.
If the connection to the J-BERT N4903B is setup correctly, then check the output
signal of the J-BERT N4903B at the Data Out, Aux Data Out (both should show a
eye diagram with an offset of -70 mV and a amplitude of 800mV). Check the output
signal of Aux Clk Out, it should give a clock signal of set set data rate with an offset
of 0V and an amplitude of 700 mV. if one of the used J-BERT N4903B outputs is
not providing the expected signal, then the J-BERT N4903B is defective.
If the J-BERT N4903B is providing the correct signals, then connect the M8061A
again and run the adjustment procedure from the
Config
screen. Check the output
of the M8061A again after the adjustment has been done. If the adjustement does
not fix the problems, then the M8061A is defective.
Check the Output of the M8061A using the Error Detector
If you have connected the M8061A to a J-BERT N4903B and have no oscilloscope
at hand, you can use the error detector for checking the output of the M8061A.
The approach shown here is checking the output signal using the error detector
of the J-BERT N4903B.
• In the ED-Clock Setup window, set the clock as internal CDR.
• Set the J-BERT’s PG and ED patterns to PRBS 15^1.
• Set the M8061A Output to 500 mV.
• Set the J-BERT’s PG Datarate to 3 Gb/s.
• Set the J-BERT’s ED Datarate to 6 Gb/s.
• In the
ED-Sampling Point Setup
window, press
Auto Align
button.
• The error detector should finish the auto alignment successfully and report a
BER of 0.000.
M8061A Status LEDs
The front panel of the M8061A includes the folloiwng LEDS:
• FAIL
• ACCESS
These LEDs have the following functionality:
• Both LEDs are on during the startup.
9
Solving Problems
522 Agilent J-BERT N4903B High-Performance Serial BERT