Figure Q4 shows the block diagram of a cascaded communication system consisting of a source with equivalent noise temperature T_s = 290 k, a passive stage with a gain of -12 dB (an attenuator, a low noise amplifier and an RF amplifier. Figure Q4 gives the gain and, where appropriate, the equivalent noise temperature of each stage. (a) Calculate the noise power in dBm at the output of a the system in 10 MHz bandwidth (assume that the physical temperature is 290 K for all stages and Boltzmann constant k = 138 times 10^-23 Note that T_e1,n = T_e1 + T_e2/G_1 +. .. + T_en/G_1G_2. .. G_(n - 1) (b) Calculate the overall signal to noise ratio (in dB) of the system given that the signal power level at the input to the attenuator is 50 nW. (c) Hence, using the Shannon-Hartley theorem calculate the channel capacity for this system. (d) Assuming that the signal power and the system bandwidth are fixed, discuss how the channel capacity could be increased. In your answer, specifically refer to your previous answers and the system components and their specifications shown in Figure Q4