Appendix B: Automatic Measurements Supported
CSA7000B Series & TDS7000B Series Instruments User Manual
B-5
Table B- 2: Comm measurements and their definition (Cont.)
Name Definition
S/N Ratio Ratio of the signal amplitude to the noise of the top or base of the signal as specified
.
S/N Ratio = (PTop -- PBase)/(PTop
sigma
or PBase
sigma
)
DutyCycleDistortion The peak-to-peak time variation of the first eye crossing measured at the MidRef as a
.
DCD (%) = 100% x TDCD
p--p
/(TCross2
mean
-- TCross1
mean
)
Quality Factor Ratio of eye size to noise.
Quality Factor = (PTop
m
an
-- PBase
m
an
)/(PTop
si
ma
+ PBase
si
ma
)
Levels Used in Taking Amplitude, Timing, and Area Measurements
Refer to Figure B--1 and the descriptions that follow to interpret the definitions
of waveforms in categories Amplitude, Timing, and Area. Low reference, mid
reference, and high reference are the default reference levels and are adjustable.
High (Histogram)
Low (Histogram)
Low (Min/Max)
High (Min/Max)
Mid reference
High reference
90%
10%
50%
Low reference
Figure B- 1: Levels used to determine measurements