Given a cascade of a preamplifier, mixer, and amplifier with the specifications shown in Table A.2,

(a) Find the gain of the preamplifier such that the overall noise figure of the cascade is 5 dB or less.(b) The preamplifier is fed by an antenna with noise temperature of 300 K (this is the temperature of the earth viewed from space). Find the temperature of the overall system using a preamplifier gain of 15 dB and also for the preamplifier gain found in part (a).

(c) Find the noise power at the amplifier output for the two cases of part (b).(d) Repeat part (b) except now assume that a transmission line with loss of 2 dB connects the antenna to the preamplifier.

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Table A.2 Gain, Noise figure, dB Bandwidth dB G1 Preamplifier Міxer 2 1.5 Amplifier 30 5 10 MHz