Topic: Electronics Engineering
If the total power of an amplitude modulated signal is 600 W and the carrier power is 400 W, the modulation index is
- A. 0.75
- B. 0.5
- C. 0.25
- D. 1
Answer: D. 1
Explanation: $P_{t} = P_{c}(1+\frac{m^{2}}{2}) \Rightarrow 600 = 400(1+\frac{m^{2}}{2}) \Rightarrow \frac{3}{2} = 1 + \frac{m^{2}}{2} \Rightarrow \frac{m^{2}}{2} = \frac{1}{2} \Rightarrow m^{2} = 1 \Rightarrow m = 1$.