Anritsu BERTWave Series, Operation Manual, Page: 62 / 466

Chapter 1 Outline
1-36
Linearity
It indicates the degree that the three Eye Amplitudes of the PAM4
waveform deviate from one third of the difference between Level 0 and
Level 3. If the three Eye Amplitudes are equal, the linearity is 1.
It is calculated with the smallest eye amplitude out of the three eye
amplitudes.
Example:
Eye Amplitude Upper: 32%
Eye Amplitude Middle: 36%
Eye Amplitude Lower: 31%
The Linearity in this case is
33.33
31
= 0.93
Mask Margin
This is the margin between the waveform and the eye mask in mask test
of eye pattern. The margin in the amplitude direction is the ratio to the
interval from the edge of the eye mask to the 1 Level or the 0 Level.
The margin in the time direction is the ratio to the time from the edge of
the eye mask to the cross point.
0%
50%
75%
Figure 1.5-20 Mask Margin
Optical Modulation Amplitude (OMA)
This indicates a difference at 1 level and 0 levels of the NRZ waveform.
It is the same as Eye Amplitude.
For PAM4 waveform, refer to “Outer OMA”.