Comtec CDM-840 Installation And Operation Manual page 35

CDM-840 Remote Router
Introduction
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 automatically operates in ACM/VCM mode. The receiver
automatically detects for spectral inversion and pilots ON/OFF, and supports spectral rolloff of
20%, 25% or 35%.
•
Sect. 1.3 Features
•
Sect. 1.4 Specifications
•
Appendix B. FEC (FORWARD ERROR CORRECTION) OPTIONS
1–3
MN-CDM840
Revision 3