HP 83487A, User Manual, Page: 40 / 98

3-4
Calibration Overview
Factory Calibrations
Factory Calibrations
The following calibrations are performed at the factory:
Mainframe Calibration
O/E Factory Wavelength Calibration
Mainframe Calibration
Mainframe calibration affects both optical and electrical measurements. Main-
frame calibration improves timebase accuracy. All timebase measurements
such as rise time, fall time, eye width, jitter, and so forth are affected by the
timebase accuracy.
The calibration factors are stored in the nonvolatile RAM of the instrument.
There is a switch on the back panel of the instrument that allows the main-
frame calibration to be protected or unprotected. Next to the switch there is a
Table 3-1. Factory Calibration Summary
Calibration What is calibrated
Measurements
Affected Recommended
Interval
Softkey Path
Mainframe
Calibration Accuracy and
continuity of the
timescale Channels affected:
optical & electrical. All
time base
measurements such as
rise time, fall time, eye
width, and jitter. Annually at HP service
center or if operating
temp has changed and
remains 5
°
C or more
from calibration
temperature. See
service manual.
Utility
Calibrate
Calibrate frame
O/E Factory
Wavelength
Calibration The photodetector
responsivity Channels affected:
optical. Amplitude
accuracy of all optical
channel
measurements. Optical
power meter accuracy. Annual factory re-
calibration of standard
wavelengths. Not user accessible. a
a. Refer to “O/E User-Wavelength Calibration” on page 3-9 .