Determine noise figure of a passive network at temperature

Question

Assignment:

1. Determine the noise figure of a passive network at temperature T₁ ≠ T₀

2. An antenna for radio transmission is pointed to a direction where the equivalent noise temperature of the sky is 50 K. The antenna output is feeding an amplifier with bandwidth B = 5 MHz, gain (gA)dB = 40 dB, and noise figure (FA)dB = 5 dB. The receiver is matched and the load at the output is purely resistive with ^{RL = 500Ω}, Determine:

a) The amplifier noise temperature and the effective input temperature of the receiver.

b) The average noise power at the system output, both in mW and dBm.

c) The standard deviation of the noise voltage across the load.