Tektronix OM4006D, User Manual

Page: 64 / 205

Operating basics
PattXlm.SyncFrameEnd = 100;
PattYRe.Values = Seq3;
PattYRe.SyncFrameEnd = 100;
PattYlm.Values = Seq4;
PattYlm.SyncFrameEnd = 100;
The code assigns the user’s pattern variables Seq1, Seq2, Seq3, and Seq4 to the
four tributaries. These variables must be loaded into the separate MATLAB
Command Window as shown in the following
fi gure.
In the case shown, a previously saved .mat fi le is loaded and the Seq variable is
created using the PattXRe.Values content. The fi gure also shows the resulting size
of the Seq variable as well as the fi rst 10 values. The pattern for each tributary
may have any length, but must be a row vector containing logical values.
Synchronizing a long pattern can take a long time. The easiest way to keep
calculations fast when using non-PRBS patterns longer than 2
15
, and if using
record lengths long enough to capture at least as many bits as in the pattern, is to
simply use the .SyncFrameEnd
fi eld as shown above. Otherwise contact customer
support for help in optimizing the synchronization.
Example capturing unknown pattern.
Another way to load the pattern variable
when using a pattern that is not one of the PRBS selections is to use the OUI to
capture the pattern and store it in a variable. Do the following:
1. Connect the optical signal with the desired modulation pattern to the OUI.
2. Set up the Analysis Parameters properly with the exception of the data pattern
which is not yet known.
3. Choose Unknown as the data pattern (do not choose “User Pattern” yet).
Optimize the signal to achieve open eye-diagrams and low EVM so that no
errors are expected.
40 OM4000D Series Coherent Lightwave Signal Analyzer