designed to lock onto a single frequency may have a tendency to lock onto
harmonics. A long PRBS may uncover such undesirable behavior.
When to Use Which Pattern?
Selecting the appropriate pattern and test setup for your application is important.
Below is a list of recommendations that may be helpful.
• To simulate random traffic, choose PRBS.
• For functional and alarm testing, choose alternating memory patterns.
• If the test pattern requires a header, choose one of the
• To stress lightwave transmitters and receivers, vary the mark density of the
pattern with a modulator or e/o converter.
• To induce baseline wander for margin testing, vary the mark density and use
alternating patterns.
• For pattern dependency testing, choose one of the
or use a custom user pattern; vary the mark density.
• For eye diagram measurements and mask analysis, use the Serial BERT with a
digital communication analyzer or oscilloscope.
• For receiver sensitivity or eye contour measurements, use the Serial BERT with
a digital communication analyzer or oscilloscope.
• For a clock recovery circuit stress test, vary the mark density or use CID
(Consecutive Identical Digit) patterns that contain long runs of 1's and 0's.
Alternatively, use the Serial BERT or a DCA with an ITU-T specified pattern for
testing STM-n systems. This pattern is to verify the adequacy of timing recovery
and low frequency performance of STM-n systems. It consists of a user pattern
that is comprised as follows:
The first row of overhead bytes for the STM-n system, all ones (zero timing
content, high average signal amplitude), pseudo-random data with 50 % mark-
density ratio. This is followed by a repeat of the pattern overhead, all zeros (zero
timing content, low average signal amplitude), and the PRBS. For full details,
see ITU-T Recommendation G.958.
• For a regenerator test, set up the bit rate according to the device specification.
T I P
If your device converts the input pattern, the error detector needs a different pattern
than the pattern generator. See
“Loading Patterns to the Pattern Generator and
for details.
3
Setting up Patterns
64
Agilent J-BERT N4903B High-Performance Serial BERT
Summary of Contents for J-BERT N4903B
Page 1: ...S Agilent J BERT N4903B High Performance Serial BERT User Guide s Agilent Technologies ...
Page 10: ...10 Agilent J BERT N4903B High Performance Serial BERT ...
Page 36: ...1 Planning the Test 36 Agilent J BERT N4903B High Performance Serial BERT ...
Page 60: ...2 Setting up External Instrument s 60 Agilent J BERT N4903B High Performance Serial BERT ...
Page 120: ...3 Setting up Patterns 120 Agilent J BERT N4903B High Performance Serial BERT ...
Page 360: ...6 Advanced Analysis 360 Agilent J BERT N4903B High Performance Serial BERT ...
Page 468: ...8 Jitter Tolerance Tests 468 Agilent J BERT N4903B High Performance Serial BERT ...
Page 524: ...9 Solving Problems 524 Agilent J BERT N4903B High Performance Serial BERT ...
Page 566: ...10 Customizing the Instrument 566 Agilent J BERT N4903B High Performance Serial BERT ...