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Appendix B: Automatic Measurements Reference
B-10
CSA8000B & TDS8000B User Manual
Table B- 2: Pulse Measurements - Timing (cont.)
Name Definition
-Duty Cycle The ratio (expressed as a percent age) of the fi rst negat ive pulse width wi thin the m easurement
region to t he period of the signal. The time intervals are determined at mid-reference level.
If Tcross1 is posi tive, then:
If Tcross1 is negat ive, then:
Tcross1, Tcross2 and Tcross3 are the times of the first three consecutive crossings at the
mid-reference level.
The mid-reference levels are adjustable and default to 50% of the pulse amplitude.
If enabled, measurement gates constrain the measurement region to the area between the Start
Gate (G1) and Stop Gate (G2). See To Localize a Measurement on page 3--83.
− Duty Cycle = 100 ×
(Tcross3 − Tcross2)
(Tcross3 − Tcross1)
− Duty Cycle = 100 ×
(Tcross2 − Tcross1)
(Tcross3 − Tcross1)
Fall Time The time interval between times of the high reference level and the low reference level
crossings on the negative sl ope of t he pulse.
RZ Fall Time = TcrossL – TcrossH
Where:
H TcrossL is the time of the crossing of the low reference level
H TcrossH is the time of crossing of the high reference level.
The low reference and high reference levels are adjustable and default to 10% and 90% of the
pulse amplitude. There are four Reference Level Calculation methods available for determining
these reference levels. See Measurement Reference Parameters and Methods on page B--56 or
in the online help and in Also see Reference Levels Method on page 3--79.
If enabled, measurement gates constrain the measurement region to the area between the Start
Gate (G1) and Stop Gate (G2). By default, the algorithm searches forward from the Start Gate
for the first falling edge, but the Direction of traversal can be reversed, so that the search will be
backward from t he Stop Gate. See To Localize a Measurement on page 3--83.
Frequency The inverse of the Period of the signal.
Where Tcross3 and Tcross1 are the t imes of the f irst t wo consecut ive crossings on the
same slope at the mid-reference level. See Pulse Crossings and Mid-reference Level on
page B--58.
The mid-reference level is adjustable and defaults to 50% of the pulse amplitude.
If enabled, measurement gates constrain the measurement region to the area between the Start
Gate (G1) and Stop Gate (G2).
Frequency =
1
(Tcross3 − Tcross1)