Topic: Analog Circuits
If each stage had gain of 10 dB and noise figure of 10 dB, then the overall noise figure of two-stage cascade amplifier will be
- A. 10
- B. 1.09
- C. 1.0
- D. 10.9
Answer: D. 10.9
Explanation: First, convert dB to absolute ratios: Gain G1 = 10, Noise Figure F1 = 10, F2 = 10. Using Friis formula: F_overall = F1 + (F2 - 1) / G1 = 10 + (10 - 1) / 10 = 10 + 0.9 = 10.9.