Comtech EF Data CDM-570 - Manual (Page 110)

CDM-570/570L Satellite Modem with Optional IP Module Revision 12
Front Panel Operation MN/CDM570L.IOM
5–24
5.2.2.1.4.5 (CONFIG: Rx) Frq (Frequency)
Rx IF Freq:1156.3456 MHz
(◄ ►,▲ ▼,ENT)
To edit the Receive IF Frequency: First, use the ◄ ► arrow keys to select a digit to edit, and then
use the ▲ ▼ arrow keys to edit the value of that digit. Press ENTER when done.
For the CDM-570L, the range of frequencies is from 950 to 2000 MHz, with a resolution of 100
Hz. Furthermore, if using the CONFIG: ODUÆLNB menus and an LNB frequency other than
zero is selected, and it is defined whether the mix is high-side or low-side, the display changes to
include the calculated Transmit RF frequency of the modem/ LNB combination, as per the
following example:
Rx IF Freq:1156.3456 MHz
RF=14156.3456(◄ ►,▲ ▼,ENT)
As the Rx IF frequency is edited, the RF frequency is automatically updated. However, for the
CDM-570, the range of frequencies permitted is from 50 to 90 MHz and from 100 to 180 MHz,
with a resolution of 100 Hz, as per the following example:
Rx IF Freq:0075.9876 MHz
(◄ ►,▲ ▼,ENT)
Note the leading zeros, which are included to maintain compatibility with the CDM-570L firmware.
5.2.2.1.4.6 (CONFIG: Rx) Acq (Acquisition Range)
Demod Acquisition Range:
+/- 010 kHz (▲ ▼,ENTER)
The Demod Acquisition Range determines the amount of frequency uncertainty the demodulator
will search over in order to find and lock to an incoming carrier. To edit the search range value,
first use the
◄ ► arrow keys to select a digit to edit, and then use the ▲ ▼ arrow keys to edit the
value of that digit. Press ENTER when done. Note the following:
• In the CDM-570L, the range varies according to symbol rate:
o ±1 kHz to ±32 kHz for rates less than or equal to 625 ksymbols/sec
o ±1 kHz to ±200 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.