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Modulation and Multiplexing: Voice, Data, Video :
Communications satellites are used to carry telephone, video, and data signals, and can use both analog and digital modulation techniques.
Modification of a carrier’s parameters (amplitude, frequency, phase, or a combination of them) in dependence on the symbol to be sent.
Task of multiplexing is to assign space, time, frequency, and code to each communication channel with a minimum of interference and a maximum of medium utilization Communication channel refers to an association of sender(s) and receiver(s) that want to exchange data One of several constellations of a carrier’s parameters defined by the used modulation scheme.
1. Voice, Data, Video :
The modulation and multiplexing techniques that were used at this time were analog, adapted from the technology developed for The change to digital voice signals made it easier for long-distance.
Communication carriers to mix digital data and telephone Fiber-optic Cable Transmission Standards System Bit rate (Mbps) 64- kbps Voice channel capacity Stuffing bits and words are added to the satellite data stream as needed to fill empty bit and word spaces.
Primarily for video provided that a satellite link's overall carrier-to-noise but in to older receiving equipment at System and Satellite Specification Ku- band satellite parameters.
2. Modulation And Multiplexing:
In analog television (TV) transmission by satellite, the baseband video signal and one or two audio subcarriers constitute a composite video signal.
Digital modulation is obviously the modulation of choice for transmitting digital data are digitized analog signals may conveniently share a channel with digital data, allowing a link to carry a varying mix of voice and data traffic.
Digital signals from different channels are interleaved for transmission through time division multiplexing TDM carry any type of traffic â€” the bent pipe transponder that can carry voice, video, or data as the marketplace demands.
Hybrid multiple access schemes can use time division multiplexing of baseband channels which are then modulate.
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