User guide

• No other advanced measurement (Output Timing, Output Levels, etc.) can be
running.
• Error Location Capture can only run when the BER Location Mode is set to
more than one bit (for example, all bits, or a block with a length > 1).
Error Location Capture - Procedures
This section shows how to set up and perform an Error Location Capture
measurement. As an example first add a couple of errors to an alternating pattern
and then capture their position.
This requires the following steps:
• Preparing the measurement (see “How to Prepare the Error Location Capture
Measurement” on page 304)
• Demonstrating the measurement (see “How to Demonstrate the Error Location
Capture Measurement” on page 305)
How to Prepare the Error Location Capture Measurement
To prepare an Error Location Capture measurement to detect the location of an
errored bit in an alternating pattern:
1
Disable the pattern generator outputs by pressing the 0V (Disable) button in
the PG Setup -> Data Output screen.
2
Use a shielded cable to connect the pattern generator's Data Out port and the
error detector's Data In port.
3
Use a second shielded cable to connect the pattern generator's Clock Out port
and the error detector's Clock In port.
4
Terminate all non-connected pattern generator output ports with 50 Ω.
5
Make sure to preset the instrument state before running the measurement:
Select Preset Instrument State from the File menu.
6
Enable the pattern generator outputs by pressing the 0V (Disable) button.
7
Press Sync Now and then Auto Align to find the optimum sampling point. Check
that the synchronization and alignment were successful. None of the error
indicators should show red.
The resulting BER should be zero.
6 Advanced Analysis
304 Agilent J-BERT N4903B High-Performance Serial BERT