HP 83487A User Manual page 56

Table 3-4. Complete Calibration Summary (2 of 3)
Calibration What is calibrated
Offset Zero Calibration Vertical offset is
calibrated for the
optical channel only.
This calibration
doesn't include
vertical scale
accuracy.
Dark Calibration Dark calibration
measures the channel
offset signal without
any light present and
this value is used in
the extinction ratio
algorithm.
Probe calibration Probe Attenuation
Channel Skew Calibrates out the
small differences in
delay between
channels. Useful for
looking at timing
differences between
channels
Calibration Overview
Complete Calibration Summary
Measurements
Affected
Channels affected:
optical. Any optical
vertical measurements
including: V p to p , eye
height, and extinction
ratio.
Channels affected:
optical & electrical.
Extinction ratio.
Channels affected:
electrical. Any
electrical
measurement taken
with the probe
Channels affected:
optical & electrical.
Multiple channel
measurements.
3-20
Recommended
Key Path
Interval
Perform a plug-in Optical Channel Setup
vertical calibration in Calibrate
order to meet Offset 0
published
specifications.
Because the offset
zero calibration
performs only the
offset portion of the
plug-in vertical
calibration, it should
only be used before
fast non-critical
measurements.
Before extinction ratio Shift, Meas eye
measurements if the Extinction ratio
vertical scale or offset Dark Cal
has changed since the
last dark calibration or
after a plug-in vertical
calibration is
performed.
Whenever a probe is Electrical Channel
connected Setup
Calibrate
Calibrate probe
Before multiple Channel Setup
channel Calibrate
measurements when Skew
measuring timing
differences between
channels.