Tektronix CSA8000B - Manual (Page 320)

Measurement Reference Parameters and Methods
B- 58 CSA8000B & TDS8000B User Manual
Tcross1
Mid-reference
Tcross2 Tcross3
Figure B- 3: Pulse crossings and mid-reference level
The following measurement parameters are normally used when measuring
Optical Modulation Amplitude on a pulse. Crossings at the measured Average
Optical Power level determine the positions of the eye apertures for the logical 1
and logical 0 of the pulse (size set in the measurement Region control). The
High, Power Logic 1, and Low, Power Logic 0 levels are determined as the mean
values of the logical levels sampled within the eye aperture of the logical 1 and 0
regions of the pulse.
Pulse Crossings and
Mid-reference Level
Pulse Crossings and
Mid-reference Level (AOP)