Comtech EF Data CDM-570A - Manual (Page 144)

CDM-570A/570AL Satellite Modem with Optional Packet Processor MN-CDM570A
Front Panel Operation Revision 2
6–40
6.3.2.10.2 (CONFIG: CnC) Freq-Offset
CnC Freq-Offset Range:
+/- 010 kHz (▲ ▼,ENTER)
Use this menu to ENTER the maximum expected frequency offset between the outbound
interferer and the desired inbound. It normally corresponds to the demod acquisition range. Use
the ▲▼arrow keys to edit the CnC Frequency Offset value. Press ENTER.
This range is pre-calculated. The Rx symbol rate determines the CnC Frequency Offset:
• From 16 to 64 ksymbols/sec (ksps): ±1 to the symbol rate (ksps/2)
• 64 ksps and above: ±1 to 32kHz
6.3.2.10.3 (CONFIG: CnC) Search-Delay
CnC Search Delay:
Min: 240 ms Max: 300 ms
To reduce the time taken for the CnC algorithm to converge, you may apply restrictions to the
range of delay used by the search. During initial link testing, you should set the delay to a
minimum of 240 ms and a maximum of 300 ms. Once CnC has found the exact delay, the value
can be further reduced but care should be taken to allow sufficient range to accommodate
changes in path delay due to Doppler.
If bench-testing CnC with two units in a back-to-back configuration, you should set
the minimum delay to 0 ms, and the maximum delay to 20 ms. This takes into
account the lack of satellite delay.
To edit the Min or Max delay, use the ◄ ► arrow keys to select a digit, and then use the
▲▼arrow keys to change that digit. Press ENTER.
6.3.2.11 CONFIG: ODU (CDM/R-570AL L-Band Units ONLY)
See Chapter 10. CDM-570A/570AL ODU (TRANSCEIVER, BUC, LNB) M&C OPERATIONS
for complete details about using this modem-specific menu branch.
ODU (Outdoor Unit):
BUC LNB (◄ ►,ENTER)
Use the ◄ ► arrow keys to configure a BUC (Block Up Converter) or LNB (Low-Noise Block Down
Converter), if connected.