Answer the following problems.

problem 1) What kind of modulation techniques may be used in optical satellite communication? describe their working in detail.

problem 2) describe in detail why it is not possible to have the direct optical communication link between earth station and communication satellite.

problem 3) Describe the modern concept of cable transmission network.

problem 4) For a satellite earth station receiver working on 4GHz, the typical various gains and noise temperatures are T_in = 50 K; T_RF = 50 K_Tm = 500 K, T_IF = 1000 K, G_RF = 23dB, G_m = 0 dB, G_IF = 30 dB. Compute the system noise temperature.

problem 5) describe SCPC and CSSB systems in detail.

problem 6) prepare brief notes on following:

(a) TDMA frame format.

(b) Reference burst in TDMA system.

problem 7) Name the satellites for earth observation and scientific studies.