Comtech EF Data CDM-840 - Manual (Page 27)

CDM-840 Remote Router Revision 2
Introduction MN-CDM840
1–3
o
ACM allows the modulator to automatically and seamlessly adjust the transmitted
MODCOD as the environmentally conditions change to maintain QEF (Quasi Error
Free) operation.
On the Tx (transmit) side: The return modulator transmits IP datagrams and is compatible with
Comtech EF Data’s CDD-880 Multi-Receiver Router(s) located at a hub site.
In the FEC encoder, the data is differentially encoded, scrambled, and then VersaFEC-encoded.
Following the encoder, the data is fed to the transmit digital filters, which perform spectral
shaping on the data signals. The resultant I and Q signals are then fed to the BPSK, QPSK, 8-QAM,
or 16-QAM modulator. The carrier is generated by a frequency synthesizer, and the I and Q signals
directly modulate this carrier to produce an IF output signal.
On the Rx (receive) side: The DVB-S2 demodulator supports enhanced GSE decapsulation and
label filtering for up to 2,047 unique labels.
DVB-S2 Receiver: The CDM-840’s demodulator supports DVB-S2 QPSK, 8-PSK, 16-APSK and 32-
APSK demodulation up to 62 Msps, with receive data rates up to 167 Mbps depending on the
modulation type and code rate.
In DVB-S2 operation, the receiver operates in the CCM mode. The receiver automatically detects
for spectral inversion and pilots ON/OFF, and supports spectral rolloff of 20%, 25% or 35%.
• Sect. 1.3 CDM-840 Features
• Sect. 1.4 CDM-840 Specifications
• Appendix B. FEC (FORWARD ERROR CORRECTION) OPTIONS
Monitor and Control Interfaces: The unit is managed through multiple interfaces providing
options for both in-band and out-of-band monitor and control:
• Sect. 6.3 (ETHERNET-BASED PRODUCT MANAGEMENT) SNMP (MIB II and
Private MIB)
• Sect. 6.4 (ETHERNET-BASED PRODUCT MANAGEMENT) Web Server (HTTP)
Interface
• Chapter 7. SERIAL-BASED REMOTE PRODUCT MANAGEMENT
On-site Firmware Updates: Field update of the operating system firmware is possible through
file upload via satellite or the Ethernet port.
Chapter 4. UPDATING FIRMWARE
On-site Operational Upgrades: Field activation of software-based options is possible through
Comtech’s FAST (Fully Accessible System Topology) Feature upgrade process.
• Chapter 5. FAST ACTIVATION PROCEDURE
• Sect. 6.4.4.2.3 (CDM-840 Web Server Interface) Admin | FAST Page