Comtech EF Data SDM-309B - Manual (Page 36)

SDM-309B Satellite Modem Operation
MN/U-SDM309B Rev. # 3–5
TX_Power Programs the modulator output power level from -5 dB to -30 dBm in .5 dB
Steps.
On entry the current transmitter power level is displayed with the flashing
cursor on the first character. The up and down keys are used to increase or
decrease the output power level in .5 dBm Steps. Press the “ENTER” key to
execute the change.
Note: If your modem has the high power Mod option installed (-11
modulator), you must change the output power range on the front panel. Enter
the Utility menu and find Pow Adj. Press the “ENTER” key and adjust the
maximum output power to read +5.0 dB using the up arrow. This will make the
TX power read +5.0 to -20.0 dB, the output range of a high power mod.
DifEncdr Programs the differential encoder On or Off.
On entry the current status of the DifEncdr is displayed with the flashing cursor
on the first character. Use the arrow keys to select ON or OFF. Press the
“ENTER” key to execute the change.
CW_Mode *Programs the modem for continuous wave mode. Three modes of operation
are available: center, dual, and offset modes.
Center Mode:
Generates a carrier at the current modulator frequency. This can be used to
measure the output power and output frequency.
Dual Mode:
Generates a dual side-band suppressed carrier signal. Side-bands are at one
half (1/2) the symbol rate from the carrier. This is used to check the channel
balance and carrier null.
Offset Mode:
Generates a single upper side-band suppressed carrier signal. The upper
side-band is at one quarter (1/4) the symbol rate from the carrier. This is used
to check the quadrature.
On entry the “CENTER” mode is displayed. To activate this test mode press
the “ENTER” key. Use the arrow keys to select the “DUAL or the “OFFSET”
modes. To return to the “CONFIG” menu press the “CLEAR” key.
Note: When the “CLEAR” key is pressed, the modem is configured to the
state it was in before “CWMode” was invoked and the transmitter is
automatically turned off to prevent the possible swamping of other channels.
To turn the transmitter on use the “RF_OUT” function.
3.1.4.2 DEMOD Configuration