Comtech EF Data CDM-700 - Manual (Page 70)

CDM-700 High Speed Satellite Modem Revision 5
Front Panel Operation MN/CDM700.IOM
6–16
If Tx Output State Æ Rx-Tx_Inhibit is selected:
Rx–Tx
Inhibit (RTI)
Prevents the Tx carrier from being transmitted, until the demodulator is locked.
To avoid the Tx Carrier from being turned Off when the demodulator loses
lock for a very short period of time, the demodulator must be unlocked
continuously for period of 10 seconds before the Tx carrier is inhibited. This
time interval is fixed.
IMPORTANT
With this feature enabled it will not affect the internal IF Loopback
feature. HOWEVER – if an external IF Loopback is attempted
(connecting an external cable from the Tx IF output to the Rx IF input),
then this feature will not function (the Tx carrier cannot turn On until
the demodulator is locked, and the demodulator cannot lock because
the Tx output is Off). The result is that the demodulator will not lock,
and the Tx carrier will not turn On.
USE THE RTI FEATURE WITH EXTREME CARE.
If Tx Power Æ Imped is selected:
IMPORTANT
The Imped(ance) selection is only available when the 70/140 MHz
Modulator card is installed.
Tx Impedance (Ohms): 50 75
( E)
This menu is displayed only when the 70/140 MHz modulator is installed.
70/140 MHz Select 50 or 75 Ω, using the ◄ ► arrow keys. Press
ENTER .
L-Band Not Applicable.
Tx:
Æ Scram
Tx Scrambling: Default-On
Off (E)
Options are:
Default-On The proprietary scrambler is selected.
Off No Scrambling.
The options are displayed all of the time, but the ◄ ► arrow keys will force the cursor to skip
past an unavailable choice. Press
ENTER
.