Exfo PSO-200 Optical Modulation Analyzer Manual de usuario descargar pdf (Pagina 259)

Optical Modulation Analyzer 251

E Measurement Definitions

Measurements follow the conventional measurement definitions from the

telecommunications industry. They are based on different histograms

obtained from the acquired samples of the signal under test.

For “constellation” measurements, the measurement procedure is

conducted on the time-less constellation graph, whereas for “Eye”

measurements, it is conducted on graphs displaying the acquired signal vs.

time, and is always conducted based on eye diagrams of the signal.

Data Used for Measurements

Both constellation and eye measurements rely on a selected portion of the

signal considered as the symbol center, which is defined in the Optical

Modulation Analyzer application using the data measurement window, as

explained in Distinguishing Data Points from Transitions on page 62. For

reliable measurements it is important to ensure a proper position and

width of this region.

The default center region is:

 For NRZ data: between 40 % and 60 % of the symbol period

 For RZ data: between 47.5 % and 52.5 % of the symbol period

All measurements are separately conducted on X and Y polarizations

tributaries of the signal under test.

Note: Statistical measurement of pattern-synchronized waveforms can be

obtained using the user-defined vertical/horizontal histograms. For details

see Viewing Signal Distribution Using Histograms on page 60.

Note: Some of the measurements are not performed in averaging mode.

Note: All X/Y polarization results come with average, minimum and maximum

values.

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Exfo PSO-200 Optical Modulation Analyzer Manual de usuario Pagina 259