Tektronix TDS7254 Stereo System User Manual


 
Appendix B: Automatic Measurements Supported
CSA7000 Series, TDS7000 Series, & TDS6000 Series Instruments User Manual
B-5
Table B- 1: Mask measurements and their definition (optional on TDS7000 Series & TDS6000 Series) (Cont.)
Name Definition
S/N Ratio Ratio of the signal amplitude to the noise of the top or base of the signal as specified
b
y
t
h
e
u
s
e
r
.
b
y
t
h
e
u
s
e
r
.
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
p
e
r
c
e
n
t
o
f
t
h
e
e
y
e
p
e
r
i
o
d
.
p
e
r
c
e
n
t
o
f
t
h
e
e
y
e
p
e
r
i
o
d
.
DCD (%) = 100% x TDCD
p--p
/(TCross2
mean
-- TCross1
mean
)
Quality Factor Ratio of eye si ze to noise.
y
y
Quality Factor = (PTop
m
e
an
-- PBase
m
e
an
)/(PTop
si
g
ma
+ PBase
si
g
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