Measurements
R&S
®
RTO6
332User 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 RT
O6 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.
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 * σtop) – (Eye base + 3 * σbase)
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 * σcrossing1)
Eye top Mean of the upper vertical histogram
Eye base Mean of the lower vertical histogram
Q factor Q factor = (Eye top – Eye base) / (σtop + σbase)
Automatic measurements