
Section
1-0ptical
Calibration Signal Generator
GENERAL INFORMATION AND SPECIFICATION
PRODUCT DESCRIPTION
The Optical Calibration Signal Generator (OSCG)
is
a
calibration fixture for the OF150 Fiber Optic Time Domain
Reflectometer. The OCSG supplies three optical signal lev-
els
that may
be
used to verify the vertical scale of the
OF150 display. These signal levels are 50 dB,
60
dB,
and
70
dB, referenced to the bottom of the display. Nine electri-
cal
signal levels are provided for calibration of the OF150
Log
Amplifier circuit. These signals are provided
in
1OdB
steps from
20
dB to 100 dB.
The OCSG has two operating modes. CAL, when select-
ed,
allows the OCSG optical output levels to
be
adjusted
and
their power content verified with
an
optical power me-
ter.
RUN,
when selected, allows the OCSG to
be
used
as
a
signal generator for calibration of the OF150. The OF150
is
the power source for the OCSG.
NOTE
The
OCSG will need to be recalibrated
if
the Fiber
Optic Cable is removed.
SPECIFICATION
The following list of instrument characteristics and fea-
tures apply to the Optical Calibration Signal Generator after
a 10 minute warmup
in
20°C ambient air.
The Performance Requirement column describes the lim-
its of the characteristic
and
the Supplemental lnformati0n
column describes features and typical values
of
information
that may
be
useful to the user.
Table 1-1
OPTICAL AND ELECTRICAL CHARACTERISTICS
Characteristic Performance Requirement Supplemental Information
Optical Output Amplitude
CAL mode
at
70
dB 0.110
µW
average power out of fiber, After adjustment
±5%
at
60
dB match 70 dB output, ± 1% After adjustment
at
50
dB match 70 dB output, ± 1% After adjustment
RUN
mode
at 70 dB 0.550
µW
average power out of fiber,
23.1
µW
peak
±10%
Optical Pulse Width After adjustment
Measured
in
4.900 ns/m
on
the OF150 DIS-
TANCE CAL
CAL mode
at 70 dB 100 meters, ± 5% 1
µs
pulse width
at
60
dB 10 X 70 dB pulse width, ± 1% 1O
µs
pulse width
at
50
dB 100 X 70 dB pulse width, ± 1% 100
µs
pulse width
RUN
mode 510 meters,
±5%
5
µs
pulse width
@
1-1