B-56 CSA8000B & TDS8000B User Manual
Measurement Reference Parameters and Methods
This reference topic describes the reference parameters (levels and crossings)
used in taking the measurements.
All Sources
The methods available for calculating reference levels used in taking automatic
measurement follow. The methods are shown using a pulse, but they also apply
to RZ and NRZ waveforms.
Reference level calculation methods
High (50 mV)
High reference
Mid reference (0 mV)
Low reference
Low (--50 mV)
90%
10% 90 mV
10 mV
-- 4 0 m V
40 mV
90 mV
10 mV
50% 50 mV 50 mV 0 mV
1. Relative Reference is calculated as percentage of the High/Low range.
2. High Delta Reference is calculated as the absolute values from the High Level.
3. Low Delta Reference is calculated as absolute values from the Low Level.
4. Absolute Reference is set by absolute values in user units.
5. AOP (not shown) measures the Average Optical Power of the waveform and uses it
as the Mid Ref level. See Pulse Crossings and Mid-reference Level AOP on page
B--58 for more information.
Figure B- 1: Reference-level calculation methods