User manual WAVECOM EASYSATSYSTEM SOFTWARE W61 VERSION 1.1

[. . . ] WAVECOM EasySatSystem Software W61 v1. 1 User Manual by WAVECOM ELEKTRONIK AG PUBLISHED BY WAVECOM ELEKTRONIK AG Hammerstrasse 8 CH-8180 Buelach Switzerland Phone Fax Email: Internet: +41-44-872 70 60 +41-44-872 70 66 info@wavecom. ch http://www. wavecom. ch © by WAVECOM ELEKTRONIK AG. Reproduction in whole or in part in any form is prohibited without written consent of the copyright owner. The publication of information in this document does not imply freedom from patent or other protective rights of WAVECOM ELEKTRONIK AG or others. All brand names in this document are trademarks or registered trademarks of their owners. [. . . ] Limiting transponders have higher power efficiency than linear transponders. Bird Slang for a communications satellite located in geosynchronous orbit. Bit A single digital unit of information. Bit Error Rate The fraction of a sequence of message bits that are in error. A bit error rate of 10e-6 means that there is an average of one error per million bits. Bit Rate The speed of a digital transmission, measured in bits per second. Byte Sequence or group of eight bits. 1 byte = 8 bits; 1 Kbyte = 1, 024 bytes; 1Mbyte = 1, 024 Kbytes; 1Gbyte = 1, 024 Mbytes. Block Down Converter A device used to convert signals in the frequency range above 1 GHz down to UHF or lower frequencies (1 GHz and lower). BPSK Binary Phase Shift Keying. A digital modulation scheme used in transmission communications. WAVECOM EasySatSystem Software W61 v1. 1 User Manual Glossary of Terms 11 Broad beam A single large circular beam that covers a large geographic area, sometimes also called Global beam. Broadcast The sending of one transmission to multiple users in a defined group (compare to unicast). Byte A sequence of eight adjacent binary digits usually treated as a unit. C/N Carrier to Noise Ratio. The ratio of the received carrier power and the noise power in a given bandwidth, expressed in dB. This figure is directly related to G/T and S/N; and in a video signal the higher the C/N, the better the received picture. C/T Carrier-to-noise-temperature ratio. Call 1. A unit of traffic measurement. Carrier The basic radio, television, or telephony center of frequency transmit signal. is modulated by manipulating its amplitude (making it louder or softer) or its frequency (shifting it up or down) in relation to the incoming signal. Satellite carriers operating in the analog mode are usually frequency modulated. Carrier Frequency The main frequency on which a voice, data, or video signal is sent. Microwave and satellite communications transmitters operate above 1 GHz (a GHz is one billion cycles per second). C-Band This is the band between 4 and 8 GHz. CDMA Code division multiple access. Refers to a multiple-access scheme where stations use spread-spectrum modulations and orthogonal codes to avoid interfering with one another. Channel A frequency band in which a specific broadcast signal is transmitted. Channel frequencies are specified in the United States by the Federal Communications Commission. Analog Television signals require a 6 MHz frequency band to carry all the necessary picture detail. Circuit mode A circuit switched operational mode for transferring (transporting and switching) user information through a network. Contrast with packet switching mode. 12 Glossary of Terms WAVECOM EasySatSystem Software W61 v1. 1 User Manual Clarke Belt The name given in honor of Arthur C. Clarke to the orbit 22, 237 miles directly above the equator where satellites can maintain a stationary position in relation to the earth. This orbit was first postulated by the science fiction writer Arthur C. Satellites placed in these orbits, although traveling around the earth at thousands of miles an hour, appear to be stationary when viewed from a point on the earth, since the earth is rotating upon its axis at the same angular rate that the satellite is traveling around the earth. Cliff effect Sudden breakdown or loss of digital signal reception when it contains more errors than the error correction system can cope with. Up to this point there is no degradation in reception quality; a significant advantage over analog where there is a gradual deterioration. Codec 1. The algorithm (HW or SW) for compressing digital voice. Co-Location Ability of multiple satellites to share the same approximate geostationary orbital assignment frequently due to the fact that different frequency bands are used. Compression A technique to reduce the amount of data to be transmitted that reduces the amount of bandwidth needed to transmit data, video or audio, thus increasing the capacity of a satellite transponder. Data Representation of facts, concepts, or instructions in a formalized manner suitable for communication, interpretation, or processing by humans or by automatic means. dB Decibel. An analog unit of measure of signal strength, volume, or signal loss due to resistance as expressed in logarithmic form. dBi The dB power relative to an isotropic source. DBS Direct broadcast satellite (for television). Refers to service that uses satellites to broadcast multiple channels of television programming directly to home mounted small-dish antennas. dBW The ratio of the power to one Watt expressed in decibels. Delay The time it takes for a signal to go from the sending station through the satellite to the receiving station. This transmission delay for a single hop satellite connection is very close on one-quarter of a second. WAVECOM EasySatSystem Software W61 v1. 1 User Manual Glossary of Terms 13 Demodulation The process for retrieving an information signal that has been modulated onto a carrier. Demodulator A unit which extracts or "demodulates" the "wanted "signals from the received carrier. DES Data Encryption Standard. [. . . ] They also provide security in that the signals appear as though they were random noise to unauthorized earth stations. Both military and civil satellite applications have developed for spread spectrum transmissions. SSPA Solid state power amplifier. Stationkeeping Minor orbital adjustments that are conducted to maintain the satellite's orbital assignment within the allocated "box" within the geostationary arc. Sub carrier A second signal "piggybacked" onto a main signal to carry additional information. In satellite television transmission, the video picture is transmitted over the main carrier. Some satellite transponders carry as many as four special audio or data sub carriers whose signals may or may not be related to the main programming. TDM Time Division Multiplexing. [. . . ]