Comtech EF Data SDM-100A - Manual (Page 43)

SDM-100A Satellite Modem Operation
Rev. 0 3–9
3.2.1.1.1 Configuration Modulator
TX-X
Code_Rate/Type Transmitter Rate selection.
One of four predefined transmitter code/data rate combinations may be
selected: A, B, C, or D, or a variable rate selection (V). These selections
must first be set up in the Utility menu.
On entry, the current transmitter rate is displayed with the flashing cursor
on the first character of the code rate on line 1. The data rate is displayed
on line 2. Press [
↑ ] or [ ↓ ] to select one of four predefined rates (A, B, C, or
D). To select the variable data rate, select “TX-V” and press [ENTER] twice.
To change the rate in the variable rate selection, press [ENTER]
when
“TX-V” is displayed. A flashing cursor will be displayed on the first character
of the coding type on line 1. Press [
← ] or [ → ] to move the flashing cursor.
Press [ ↑ ] or [ ↓ ] to increment or decrement the digit at the flashing cursor.
Press [ENTER] to execute the change.
To operate BPSK, select “TX-V” and select BPSK 1/2 for the code rate,
then enter the data rate from 9.6 to 64 kbit/s. Press [ENTER]
to execute the
change.
Note: When the TX Rate has been changed, the transmitter is
automatically turned off to prevent swamping of other channels. To turn the
transmitter on, use the “IF Output” function.
TX-IF Frequency Programs the modulator transmit frequency between 50 and 180 MHz, in
2.5 kHz steps.
On entry, the current transmitter frequency is displayed with the flashing
cursor on the first character. Press [
← ] or [ → ] to move the flashing cursor.
Press [ ↑ ] or [ ↓ ] to increment or decrement the digit at the flashing cursor.
Press [ENTER] to execute the change.
Note: When the transmitter frequency is changed, the transmitter is
automatically turned off to prevent the possible swamping of other
channels. To turn the transmitter on, use the “IF Output” function.
TX-IF Output Programs the modulator output to ON or OFF.
On entry, the current status of the output is displayed. Press [
↑ ] or [ ↓ ] to
select ON or OFF. Press [ENTER] to execute the change.