Question

VS W l such a junction? (5 c) Suppose a (200+j75)- load is to be matched to a 300-2 transmission line to give SWR = 1. Determine the reactance of the stub and the characteristic impedance of the quarter-wave transformer, both connected directly to the load. d) (5 marks) i. For a given communication system, briefly explain the meaning of the following terms: Thermal Noise, Noise Figure, and Noise Temperature. A given communication system has a 12 GHz receiver that consists of an RF stage with gain Gi 30 dB and noise temperature Tr 20K, a down converter with gain G2 ii. 10 dB and noise temperature T = 360K and an IF amplifier stage with gain 15 dB and noise temperature T 1000K. Calculate the effective noise GJ temperature and noise figure of the system. Take the reference temperature to be 290K. (6 marks) 2. a) Distinguish between microcells and macrocells in mobile communications. (4 marks) b) With the aid of a suitable diagram, explain the operation of the hybrid T- junction (magic Tee). What are its applications? What is done to avoid reflections within such a junction? (5 marks) c) Suppose a (200+ j75)-2 load is to be matched to a 300-2 transmission line to give SWR 1. Determine the reactance of the stub and the characteristic impedance of the quarter-wave (5 marks) transformer, both connected directly to the load. d) i. For a given communication system, briefly explain the meaning of the following terms: Thermal Noise, Noise Figure, and Noise Temperature. ii. A given communication system has a 12 GHz receiver that consists of an RF stage with gain G; 30 dB and noise temperature Ti 20K, a down converter with gain G2 10 dB and noise temperature T2 360K and an IF amplifier stage with gain 15 dB and noise temperature T3 1000K. Calculate the effective noise temperature and noise figure of the system. Take the reference temperature to be (6 marks) G3 290K.

Answer 1

Q.no 2 (a), (b) are solved are given below:-

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