Question 5 [20 Marks] a) A low noise amplifier (LNA) is connected to a receiver which has a noise figure of 12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculate the overall noise temperature referred to the LNA input. Assume that the room temperature is 290 K. (5 Marks b) For the system shown in Fig. Q5, the receiver noise figure is 12 dB, the cable loss is 5 dB, the LNA gain is 50 dB, and its noise temperature 150 K. The antenna noise temperature is 35 K. Calculate the noise temperature referred to the input. [5 Marks) Assume that the room temperature is 290 K. LNA G Cable Toot Receiver noise factor F loss L: 1 Figure Q5. The system for Question 5. c) In a satellite link, with the following information, T = 400 K: The overall noise temperature EIRP = 120 W: Effective Isotropic Radiated Power of antenna L = Pass loss=10% B=Bandwidth=40 MHz G, = Receive antenna gain=200 If the total transponder gain (g) and the section gain on the downlink (ga) are 400 and 1000 and the total system noise temperature in the uplink side is 3 times of downlink side, find the total noise- to-carrier ratio. [10 Marks] Question 5 [20 Marks] a) A low noise amplifier (LNA) is connected to a receiver which has a noise figure of 12 dB. The gain of the LNA is 40 dB, and its noise temperature is 120 K. Calculate the overall noise temperature referred to the LNA input. Assume that the room temperature is 290 K. (5 Marks b) For the system shown in Fig. Q5, the receiver noise figure is 12 dB, the cable loss is 5 dB, the LNA gain is 50 dB, and its noise temperature 150 K. The antenna noise temperature is 35 K. Calculate the noise temperature referred to the input. [5 Marks) Assume that the room temperature is 290 K. LNA G Cable Toot Receiver noise factor F loss L: 1 Figure Q5. The system for Question 5. c) In a satellite link, with the following information, T = 400 K: The overall noise temperature EIRP = 120 W: Effective Isotropic Radiated Power of antenna L = Pass loss=10% B=Bandwidth=40 MHz G, = Receive antenna gain=200 If the total transponder gain (g) and the section gain on the downlink (ga) are 400 and 1000 and the total system noise temperature in the uplink side is 3 times of downlink side, find the total noise- to-carrier ratio. [10 Marks]