Concepts and features
R&S
®
ZNB/ZNBT
232
User Manual 1173.9163.02 ─ 62
Figure 4-19: Eye Diagram Result Info Field
The following results are available:
●
Eye Minimum
and
Eye Maximum
These values represent the minimum and maximum outputs of the eye diagram
processing. These values include any over- and under-shoots seen during the
symbol transitions.
●
Eye Base
,
Eye Top
,
Eye Mean
, and
Eye Amplitude
"Eye Base" and "Eye Top" represent the averaged voltages observed for the low
and high voltage bits, respectively. "Eye Mean" is the average of "Eye Top" and
"Eye Base", "Eye Amplitude" is the difference between "Eye Top" and "Eye Base".
●
Eye Height
This result indicates the effects of noise in reducing the vertical eye opening. It is
defined as ("Eye Top" - 3σ
Top
) - ("Eye Base" + 3σ
Base
), where σ
Top
and σ
Base
denote
the standard deviations of the observed high and low voltage levels, respectively.
●
Eye Width
This result indicates the effects of jitter in reducing the horizontal eye opening. It is
defined as "Bit Period" - 2 · 3 · "Jitter RMS".
●
Bit Period
The inverse of the data rate.
●
Rise Time
and
Fall Time
The time it takes the rising (falling) edge of the eye to go from x% (y%) of the "Eye
Amplitude" to y% (x%) of the "Eye Amplitude" (0≤x≤y≤100, typically x=10 and
y=90).
●
Jitter Pk-Pk/RMS
These values measure the excursion of the 50% point of the rising edge in the hori-
zontal (time) direction: "Jitter Pk-Pk" is the distance between the peak values; "Jit-
ter RMS" is the RMS value of the excursions.
●
Duty Cycle Dist/Pct
These values measure the time separation between the rising and falling edge at
the 50% level of the eye diagram. "Duty Cycle Dist" is the absolute distance, "Duty
Cycle Pct" gives the same value as a percentage of the "Bit Period".
●
Crossing Percent
The Crossing Height is the height above "Eye Base" where the rising and falling
edges cross, "Crossing Percent" gives the same value as a percentage of the "Eye
Amplitude".
Optional extensions and accessories
