Noise figure of a vacuum tube amplifier

Question

Question 1: State the noise figure of an amplifier. Compute the overall noise figure of ‘n’ cascaded networks, having gains A₁, A₂……….A_n and individual noise figure source, F₁, F₂,……..F_n correspondingly.

Question 2: Describe in brief the terms noise figure and noise temperature.

Question 3: If F₁ and F₂ are the noise figures and G₁ and G₂ are available power gains of two amplifiers in cascaded, illustrate that the overall noise figure F is given by F = F₁ + F₂ -1/G

Question 4: State the noise figure of an amplifier. Compute the noise figure of a vacuum tube amplifier supposing appropriate parameter.

Question 5: Describe different kinds of noise in:

a) Junction diodes.
b) Junction transistors.

Question 6: Explain an experimental setup for the measurement of noise figure showing that the noise figure F is independent of the network gain and input resistance.

Question 7: Describe the Sources of noise in semiconductors. Determine the noise figure of grounded base transistor amplifier.

Question 8: Illustrate that the noise figures of grounded cathode, grounded grid and grounded plate vacuum tube amplifiers are approximate the similar.

Question 9: Write descriptive notes on the given:

a) Minimum noise network
b) External noise

Question 10: What are various types of non-man made noise which might arise in a communication system? Describe the origin and nature of each kind.