Configuration Demodulator - Comtech EF Data SDM-650B Installation And Operation Manual

SDM-650B Satellite Modem
F.5.2.1.2 Configuration Demodulator
Refer to Table F-5.
RX-x
RX_Freq
Dscrmblr
IFLoopBk
(Test Mode Configuration
Option)
RFLoopBk
(Test Mode Configuration
Option)
Rev. 5
Receiver Rate Selection. Select one of four pre-defined receiver
decoder/data rate combinations or a variable rate selection.
On entry, the current receiver 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. Use the arrow keys to select one of four pre-defined
rates. Filters that are not present may display N/A (not assigned). They
cannot be programmed. If the modem is equipped with the variable rate
option, TXV can also be selected. Enter the desired data rate.
Programs the demodulator receive frequency between 50 and 90 MHz,
or 100 and 180 MHz, in 2.5 kHz steps.
On entry, the current receive frequency is displayed with the flashing
cursor on the first character. Use [
cursor. Use [ ] and [ ] to increment or decrement the digit at the
↑ ↓
flashing cursor. Press [ENTER] to execute the change.
Programs the demodulator/decoder for descrambler ON or OFF.
On entry, the current status of the descrambler is displayed with the
flashing cursor on the first character. Use the arrow keys to select ON
or OFF. Press [ENTER] to execute the change.
Programs the modem for IF loopback operation.
When the IF loopback is turned ON, the demodulator input is connected
to the modulator output through an internal attenuator. The demodulator
is programmed to the same frequency as the modulator. An attenuator
within the modem connects the IF Out to the IF In. When IF loopback is
turned OFF, the demodulator is tuned to its previous frequency, and is
reconnected to the IF input.
On entry, the current status of the IF loopback is displayed with a
flashing cursor on the first character. Use the arrow keys to select ON
or OFF. Press [ENTER] to execute the change.
Programs the modem for RF loopback operation.
When RF loopback is turned ON, the demodulator is programmed to
the same frequency as the modulator. When RF loopback is turned
OFF, the demodulator is tuned to its previous frequency.
On entry, the current status of the RF loopback is displayed with the
flashing cursor on the first character. Use the arrow keys to select ON
or OFF. Press [ENTER] to execute the change.
Asynchronous Overhead Channel Unit
← ] and [ → ] to move the flashing
F–23