Answers TMTC

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1) Highlight the causes of attenuation of the signal in a telecommunication system: Atmospheric losses, dependent on frequencies, caused mainly by the presence of H20 particles (30 GHZ resonance) and Oxygen (60 GHz). Rain losses, probabilistic event, causes a disruption of the link for a certain period of time. Fog and cloud losses. Space losses. Relative misallignment of the antennas. Cable transmission losses. Implementation of the modulation and the encoding can be also seen as a loss. 2)BPSK (Based Phase Shift Keying) is a digital modulation which relates one symbol to 1 bits, modulates the phase of the signal between 0° (0) and 180° (1) phase (discretized). FSK (Frequency Shift Keying) as the name says modulates the frequency in two possible values f1 and f2 3)It’s a long Answer. One possible way to proceed could be the identification of the lossesset up the link budget by choosing values of power, antennas gain, BER, modulation, data rate, choose of the frequency ( the frequency have to be chosen in terms of Internation Telecommunication Union disposability where you have to communicate with earth, otherwise choose it just on the base of the losses, or the bandwidth you need). The output of the link budget should guarantee a value of the Link Margin of at least 3dB (link margin = Signal to noise ratio- signal to noise ratio required). Antenna size and amplifier power are dependent: one grows, the other lower at constant LM. With power values higher than 10 W TWTA (travelling wave tube amplifier) is preferred, if lower, solid state amplifier. 4)space losses are losses due to the propagation of the wave by considering the source of the emission as a point radiating in all the directions: the grow with the square of the distance (it’s like a sphere becoming bigger…