Topic: Communication Systems
In an amplitude modulated system if the total power is 600 W and the power in the carrier is 400 W, the modulation index is
- A. 0.5
- B. 0.75
- C. 0.9
- D. 1
Answer: D. 1
Explanation: $P_{t}=P_{c}(1+\frac{m^{2}}{2}) \Rightarrow 600=400(1+\frac{m^{2}}{2}) \Rightarrow 1+\frac{m^{2}}{2}=\frac{3}{2} \Rightarrow \frac{m^{2}}{2}=\frac{1}{2} \Rightarrow m^{2}=1 \Rightarrow m=1$.