HP 83487A User Manual page 44

Table 3-2. Optical and Electrical Channel User Calibration Summary
Calibration What is calibrated
O/E User Wavelength The photodetector
Calibration responsivity
Plug-in Vertical Vertical offset and
Calibration vertical scale accuracy
for both electrical and
optical channels.
Offset Zero Vertical offset is
Calibration 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.
Calibration Overview
User Calibrations—Optical and Electrical
Measurements
Affected
Channels affected:
optical. All optical
channel
measurements at user
wavelengths.
Channels affected:
optical & electrical.
Any optical or
electrical vertical
measurements such as
V p to p , eye height,
extinction ratio, and
the optical power
meter
Channels affected:
optical. Any optical
vertical measurements
including: V p to p , eye
height, and extinction
ratio.
Channels affected:
optical & electrical.
Extinction ratio.
3-8
Recommended
Key Path
Interval
Annual re-calibration Optical Channel Setup
of user defined non- Calibrate
factory wavelengths O/E Cal
Perform after any Utility
power cycle or once Calibrate
every 10 hours during Calibrate Plug-in
continuous use or if
operating temperature
changes by more than
2°C.
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.