Comtech EF Data SDM-9000, Installation And Operation Manual

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Operation SDM-9000 Satellite Modem
4–8 Rev. 4
CARRIER MODE
(Test Mode Configuration
Option) Programs the modem for continuous wave mode. Four modes
of operation are available:
•
Normal (OFF)
•
Center
•
Offset
•
Dual
Normal (OFF) Mode:
The Carrier mode is normally in the OFF position. To execute
any of the Carrier continuous wave modes, the user must
enter the Carrier mode and select the test mode of choice.
Center Mode:
Generates a carrier at the current modulator frequency. This
can be used to measure the output frequency.
Offset Mode:
Generates a single upper sideband suppressed carrier signal.
The upper sideband is at one-quarter of the symbol rate from
the carrier. This is used to check the quadrature.
Dual Mode:
Generates a dual side-band suppressed carrier signal.
Sidebands are at one-half of the symbol rate from the carrier.
This is used to check the channel balance and carrier null.
On entry, the Center mode is displayed. To activate this test
mode, press [ENTER]. Press [
←
] or [
→
] to select the Dual or
Offset modes.
To return to the Configuration menu, press [CLEAR].
Note: When [CLEAR] is pressed, the modem is configured to
the state before CW mode was invoked. The TX is
automatically turned off to prevent the possible swamping of
other channels. To turn the TX on, use the IF Output function.
MODULATOR REF Optional program for selecting the high stability 5 MHz internal
reference and the 5, 10, and 20 MHz external references.
On entry, the Internal mode is displayed. Press [
↑
] or [
↓
] to
select external 5 MHz, external 10 MHz, or external 20 MHz
references. Press [ENTER] to execute the change.
RS ENCODER Programs the Reed-Solomon encoder on or off.
On entry, the current status of the Reed-Solomon encoder is
displayed. Press [
←
] or [
→
] to select ON or OFF. Press
[ENTER] to execute the change.
Note: Programming the Reed-Solomon encoder automatically
turns off the RF TX (because of symbol rate changes).