A digital microwave terrestrial link has an antenna located on the outside of a building some distance from the receiver. The attenuation of the cable connecting the antenna to the receiver is 12dB, at the operating frequency. The noise figure of the circuits in the receiver before the threshold detection circuit is 9dB. (Assume that the system is matched throughout and that all parts are at 290K, Boltzman's constant is 1.381023JK1.) (a) What is the overall system noise temperature and noise figure? (6 marks) (b) Given that the available signal power from the antenna is 81011W, the relevant bandwidth is 60MHz and the antenna noise temperature is 230K. What is the signal to noise ratio at the receiver threshold detection circuit? (4 marks) (c) Two amplifiers are available which could be used as preamplifiers located at the antenna. One has a gain of 7dB and a noise figure of 2dB; the other has a gain of 10dB and a noise figure of 5dB. Which of the two results in the better system performance, and what, in that case, is the signal to noise ratio at the threshold detection circuits? A digital microwave terrestrial link has an antenna located on the outside of a building some distance from the receiver. The attenuation of the cable connecting the antenna to the receiver is 12dB, at the operating frequency. The noise figure of the circuits in the receiver before the threshold detection circuit is 9dB. (Assume that the system is matched throughout and that all parts are at 290K, Boltzman's constant is 1.381023JK1.) (a) What is the overall system noise temperature and noise figure? (6 marks) (b) Given that the available signal power from the antenna is 81011W, the relevant bandwidth is 60MHz and the antenna noise temperature is 230K. What is the signal to noise ratio at the receiver threshold detection circuit? (4 marks) (c) Two amplifiers are available which could be used as preamplifiers located at the antenna. One has a gain of 7dB and a noise figure of 2dB; the other has a gain of 10dB and a noise figure of 5dB. Which of the two results in the better system performance, and what, in that case, is the signal to noise ratio at the threshold detection circuits