25
Noise
This library is a consolidation of all vertical
noise measurements including rms and
deterministic noise. For an optical DUT signal
this will be depicted in Watts.
SNR
The signal to noise is a ratio of the signal
difference between one level and zero level
relative to the noise present at both levels.
VEC
VEC = Vertical Eye Closure in dB.
Calculated in NRZ as:
20 ×
log
(
𝐸𝑦𝑒 𝐴𝑚𝑝𝑙𝑖𝑡𝑢𝑑𝑒
𝐸𝑦𝑒 𝐻𝑒𝑖𝑔ℎ𝑡
)
]
Calculated in PAM 4 as:
20 ×
log
[𝑀𝑎𝑥 (
𝐴𝑉
𝑢𝑝𝑝
𝑉
𝑢𝑝𝑝
) , (
𝐴𝑉
𝑚𝑖𝑑
𝑉
𝑚𝑖𝑑
) , (
𝐴𝑉
𝑙𝑜𝑤
𝑉
𝑙𝑜𝑤
)]
]
Note: AV is the eye amplitude and V is the eye
height in PAM4 mode.
Eye Skews
Ratio Level Mismatch is a measure of linearity
in a PAM4 signal. This measurement is
defined by the IEEE as a metric to compare
the consistency of the three eye openings of
a PAM4 signal. Please refer to the 120D-6
IEEE annex for the relevant equation.
R
LM
Ratio Level Mismatch is a measure of linearity
in a PAM4 signal. This measurement is
defined by the IEEE as a metric to compare
the consistency of the three eye openings of
a PAM4 signal. Please refer to the 120D-6
IEEE annex for the relevant equation.
