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EXFO PSO-200 Optical Modulation Analyzer User Manual

Page 256

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Modulation Schemes

248

PSO-200

For simplicity purposes, transitions corresponding to higher-order formats
are not illustrated here. The symbol mapping, {B

3

,B

2

,B

1

,B

0

}'{I,Q}),

depends on the specific implementation, and there are several possible
implementations for most modulation formats.

The PSO-200 default implementation and mapping of each modulation is
shown in the table below. To implement a different mapping, you must edit
the Gearbox configuration file as explained in Performing Detailed Bit
Pattern Analysis with the Gearbox
on page 87.

Modulation

Format

Bits/

Symbol

Constellation

Chart

Default

Implementation

Mapping

CW

No modulation

OOK

1

Remark: M = x-cut or

z-cut MZ biased at /4

BPSK

1

Remark: M = x-cut

MZ biased at 0

MZM

X0

B

0

I

Q

0

0

0

1

1

0

MZM

X0

B

0

I

Q

0

-1

0

1

1

0