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INSTALLATION AND SETUP
The OTDC-440 is designed to be mounted in a standard 19" equipment rack. Mount it in a rack using 4 screws
of the proper size for the rack in use. It is a good idea if possible, to allow 1 empty rack space above and
below this unit to allow good flow of cooling air. If it is operated on a bench or table, it is best not to stack other
equipment on top of it.
Connect the OTDC-440 to a source of AC power. It may be powered with 90 to 250VAC at 50 or 60Hz. The
AC line fuse is inside the unit in the power supply module. If it becomes necessary to replaces this fuse, replace
it with the same type 5x20mm, 2A, 250V fuse. Do not remove the cover of the OTDC-440 with AC power
applied.
The OTDC-440 has an AGC system to maintain relatively constant RF output levels as the optical input signal
varies over a range of approximately –8dBm to
±
0dBm. The output level of the OTDC-440 is directly related
to the RF input level at the upconverter system. For OLSON systems, the RF output level is set at the factory
to approxi35dBmV for an upconverter input level of +15dBmv.
The system will function well with optical levels as low as –12dBm into the OTDC-440 but the RF output level
will go down as the optical input level goes below approximately –8dBm. It is recommended that the optical
input level to the OTDC-440 be set between -8dBm and
±
0dBm.
The front panel has two DC test points. Each of these is referenced to chassis ground and should be measured
with a DMM.
The AGC test point allows measurement of the AGC level and will normally be approxi2.3VDC with
an optical input level of –4dBm. Once the system is set-up and in operation, the voltage at this test point can be
measured and recorded for historical purposes.
The OPTICAL POWER test point allows measurement of the optical input level at the optical detector diode
inside the unit. This test point is calibrated at 1VDC per mW and may be used as an accurate indication of
optical input power. Once the system is set-up and in operation, the voltage at this test point can be measured
and recorded for historical purposes.
The controls on the rear panel marked BAND 1, 2, 3, and 4 MGC are factory-set and should not be adjusted.
The 5-42MHz RF outputs are marked Band 1 through Band 4 on the rear panel. These band designations are
directly related to the designations on any OLSON fixed block upconverter. A signal fed to the BAND 1 input
on a block upconverter such as the FRMUC will appear at the BAND 1 output on the OTDC-440.
