1. SHAHEEM TM | S7 | 24

2. A communications satellite exists to provide a platform in relaying of voice,video and data communications.all other subsystems on the satellite exist to support the communication system only. The main objective of communication system is to provide a reliable communication between the satellite and ground station

3. Functions of communication subsystem To capture the carriers transmitted by the earth station. To amplify the received carriers. To change the frequency of the carriers from the uplink to the downlink (14 to 11ghz). To provide the power required for down-link transmission. To radiate the carriers in the given frequency band and with the required polarization.

4. Transmitting and receiving frequency bands The effective isotropic power radiated in a given direction. The figure of merit of the receving system(G/T )ratio. The nonlinear characteristics The reliability after N-Years. The EIRP required at the satellite in order to produce the required performance.

5. Transmitting and receiving antennas. Amplifiers,low noise amplifiers and High power amplifiers Filters,Rf and IF band pass Oscillators Up and Down converters Multiplexers and de-multiplexers Electrical switches.