Teledyne LeCroy WaveExpert 100H Operators Manual - Manual (Page 157)

Wave Expert
WE-OM-E Rev A
155
menu also has controls to enter two sources. The Source1 control is the primary input for all of the
selected eye parameters, while Source2 is used by eye parameters measured between two eye
patterns. Sources for eye measurements can be any channel when the instrument is in Eye mode,
and the eye pattern measured in Serial Data Analysis mode (Eye) when the WE-SDA option is
installed.
The amplitude related parameters associated with NRZ signals are based on the one and zero
levels, as measured within the eye aperture, which is defined as a percentage of the unit interval
centered in the eye. The default percentage is 20%. The one and zero levels are measured as the
mean of histograms around the high and low levels within the eye aperture. The level at 50%
between the high and low levels at 10% and 90% are used by parameters such as rise time. NRZ
measurements operate on the histogram mean of the persistence map.
Parameter Description Definition Notes
Ext Ratio Extinction ratio
( )
( )
d
d
P P
P P
ER
−
−
=
0
1
Dark calibration
required to determine
Pd. Result can be
displayed in %, dB
(10log(ER)).
Eye AC RMS RMS value of the signal
within 1 unit interval UI
Eye Amplitude Difference between the
0 and 1 levels
0 1
P P Eampl
− = P1 and P0 are the mean
of the amplitude.
Eye BER Estimated BER based
on eye amplitude and
noise level
π
2
2
2
Q
e
BER
Q −
=
Q is the Q factor. BER
assumes optimum
sampling position within
the eye.
Eye Bit Rate Bit rate based on the
inverse of the measured
unit interval
UI
BR
1
=
Eye Bit Time Duration of one unit
interval