Mocomtech CDM-570 - Manual (Page 149)

CDM-570/570L Satellite Modem with Optional IP Module Revision 4
Front Panel Operation MN/CDM570L.IOM
6–25
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.
In the CDM-570L. the range varies according to symbol rate:
+/- 1 kHz to +/- 200 kHz for rates less than or equal to 625 ksymbols/sec
+/- 1 kHz to +/- 32 kHz for rates greater than 625 ksymbols/sec
In the CDM-570, the range is +/- 1 kHz to +/- 32 kHz.
CAUTION MUST BE EXCERCISED at low data rates where the acquisition range is
greater than the symbol rate of the desired carrier. In this circumstance it may be possible
to acquire lock on an adjacent (and hence undesired) carrier, if that carrier has identical
characteristics (modulation, FEC, code rate, data rate, etc.) to the carrier of interest.
6.8.7 (CONFIG, RX) DESCRAMBLING
Options are:
Default-On - the appropriate descrambler type is automatically selected.
IESS-315-On - this only applies when Turbo is installed and has been selected as the
FEC type .
Off - no descrambling.
As before, the 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:
Uncoded:
ITU V.35 (Intelsat variant)
Viterbi, no framing: ITU V.35 (Intelsat variant)
Viterbi, EDMAC frame: Comtech proprietary, frame synchronized
Viterbi + RS or TCM/RS: Per IESS-308, frame synchronized
TPC or LDPC: Comtech proprietary, frame synchronized
Descrambling: Default-On
IESS-315-On Off (
◄ ►,ENT)
IMPORTANT
IMPORTANT