Mocomtech CDM-QX - Manual (Page 91)

CDM-Qx/QxL Multi-Channel Satellite Modem with DoubleTalk™ Carrier-in-Carrier® Revision 7
Front Panel Operation MN/CDMQX.IOM
5–25
5.4.3.6 CONFIG: Rx
Æ Acq
Demod Acquisition Range:
+/- 32 kHz (▲ ▼ ENT)
For the Receive Demodualtion Acquisition Range, the value entered here determines the amount
of frequency uncertainty the demodulator will search over in order to find and lock to an
incoming carrier.
Edit the range by first using the W X arrow keys to select the digit to be edited; the value of the
digit is then changed using the ST arrow keys. Press
ENTER
when done.
Note the following:
• The range varies from ± 1 kHz to ± 32 kHz for 70/140 IF, ± 1 kHz to ±(symbol rate/2) up
to ±200 kHz for L-Band.
• For symbol rates < 64 ksps, it will be ± (symbol rate/2).
• For L-Band, Acquisition Range < 625 ksps = ± 32 kHz, ≥ 625 ksps = ± 200 kHz.
5.4.3.7 CONFIG: Rx
Æ Descram
Descrambling: Default-On
IESS-315-On Off (◄ ►,ENT)
To set the Receive Descrambling mode, select Default-On, IESS-315-On, or Off using the ◄ ►
arrow keys, then press
ENTER
. Note the following:
Default-On The appropriate scrambler type is automatically selected
IESS-315-On This only applies when Turbo is installed and has been selected as the FEC type
Off No scrambling
Descrambler Selection Notes
As noted previously, all options are displayed all of the time, but the ◄ ► arrow keys will force
the cursor to skip past an unavailable choice.
The default descrambler types are as follows:
Viterbi, no framing: ITU V.35 (Intelsat variant)
Viterbi, EDMAC frame: Comtech proprietary, frame synchronized
Viterbi + R-S or TCM/R-S: Per IESS-308, frame synchronized
TPC: Comtech proprietary, frame synchronized
IMPORTANT