Noise figure is defined as
- A. $F=\frac{S_i/N_i}{S_0/N_0}$
- B. $F=\frac{S_0/N_0}{S_i/N_i}$
- C. $F=\frac{S_0/N_0}{\sqrt{S_i/N_i}}$
- D. $F=\frac{S_i/N_i}{\sqrt{S_0/N_0}}$
Answer: A. $F=\frac{S_i/N_i}{S_0/N_0}$
Explanation: Noise figure (F) is the ratio of the signal-to-noise ratio at the input to the signal-to-noise ratio at the output.