Comtech EF Data CDM-760 - Manual (Page 367)

H–1
Appendix H. CARRIER ID (DVB-
CID M
ETA
C
ARRIER
®)
H.1 Overview
Radio Frequency Interference (RFI) is the largest single issue that impacts Quality of Service for
satellite operators. CID (Carrier Identification) is a means to combat radio frequency
interference.
The CDM-760 Advanced High-Speed Trunking Modem incorporates a patent-pending CID
technique that uses MetaCarrier® spread spectrum technology to embed a unique carrier
identification sequence for the transmitted carrier.
Since the initial release of this technology in the CDM-760, the European Telecommunications
Standards Institute (ETSI) has adopted a modified version of Comtech’s original scheme, which
is defined in ETSI TS 103 129 – Digital Video Broadcasting (DVB) Framing Structure, Channel
Coding and Modulation of a Carrier Identification System (DVB-CID) for Satellite Transmission.
CDM-760s running Firmware Version 1.2.1 or later fully comply with this new specification.
The CDM-760 with MetaCarrier® is used in tandem with the Comtech EF Data MCDD-100
MetaCarrier® Detection Device to provide a complete MetaCarrier embedding and decoding
solution.
H.1.1 About MetaCarrier
The DVB-CID (MetaCarrier) concept employs a low-speed data sequence containing identifying
information about a host carrier that is spread using Direct Sequence Spread Spectrum (DSSS),
and then combined, at a low power level, directly underneath that host carrier. The composite
signal therefore carries its own embedded identification. The power level and bandwidth of the
MetaCarrier is sufficiently low that it is completely hidden below the host carrier, and has
minimal effect on system Eb/No (approximately 0.1 dB).
DVB-CID operates independent of the modulation and Forward Error Correction (FEC) rate of
the host carrier. In configurations where the carrier is encrypted or uses cryptographic
technologies, the information carried in the DVB-CID is not affected.