Measurements
R&S
®
RTO6
332
User Manual 1801.6687.02 ─ 05
8.2.6.1
Overview of eye diagram measurements
Table 8-6: Eye measurements
Meas. type
Description/Result
%
Extinction ratio (%)
The extinction ratio is an indication of efficiency. It describes the ratio of
the power used to transmit a logic level 1, to the energy used to trans-
mit a logic level 0. The R&S
RTO6 provides extinction ratio measure-
ments as a percentage, and in decibels:
ER (%) = Eye base / Eye top *100
Prerequisite: Eye base > 0 and Eye top > 0 because extinction ratio is
defined only for positive values.
dB
Extinction ratio (dB)
ER (dB) = 10*log (Eye top / Eye base)
Eye height
The vertical eye opening indicates the sensitivity of the transmission to
noise.
(Eye top – 3 *
σ
top) – (Eye base + 3 *
σ
base)
Eye width
The horizontal eye opening indicates the time range during which the
sampling of the logical state is possible.
(Tcrossing2 – 3 *
σ
crossing2) – (Tcrossing 1 – 3 *
σ
crossing1)
Eye top
Mean of the upper vertical histogram
Eye base
Mean of the lower vertical histogram
Q factor
Q factor = (Eye top – Eye base) / (
σ
top +
σ
base)
Automatic measurements
