2010-10-26 Network Design and Engineering Guide 141Appendix C - Glossary8 APPENDIX C - GLOSSARYTerm DefinitionAntenna For satellite communication over geosynchronous satellitesparabolic reflector antennas are used.Backup Master A slave station that is ready in terms of hardware, software andconfiguration to take over the role of a master station. See alsoMaster Station.Bandwidth A range of frequencies within a spectrum, expressed in Hertz.Also used for the data transfer rate or throughput, expressedin bits per second.Beam Radio transmission focused into a certain direction in order toachieve a high power density in that direction.Bit Rate Speed of transmission, measured in bits per second (bps).Binary Phase Key Shifting(BPSK)Modulation scheme that uses two phases separated by 180degrees.Block Up Converter (BUC) Used for transmission towards the satellite (uplink); convertsfrom a lower frequency to a higher frequency using a fixed os-cillator frequency.Burst A short transmission over the satellite link. The burst time issmaller than the time slot.Carrier to Noise Ratio(C/N)The ratio of the received carrier power and the noise power ina given bandwidth expressed in dB. The higher the C/N thebetter the quality.C band Frequency band with uplink 5.925 to 6.425 GHz, downlink 3.7to 4.2 GHz.Container Part of a data burst reserved for user traffic.Coverage Footprint or the area on the earth's surface that is covered bya satellite's transmission beam.Cross Strapped Trans-ponderA bent pipe transponder with uplink and downlink coverage lo-cated in different areas, e.g. uplink in Europe, downlink in USA.See also Transponder.Datagram Unit of transmission in the network layer (such as IP). A data-gram may be encapsulated in one or more packets passed tothe data link layer.dBW The ratio of the power to one Watt expressed in decibels. Typ-ically the EIRP of satellite beams are measured in dBW.Double Hop Transmission of information from one terminal to another ter-minal in two stages via an intermediate hub station. Typical forstar networks.
