Question

An AM signal with a carrier of 1 KW has 100 W power in each side band. The modualtion index is *


a)0.446

b)0.324

c)0.6324

d)0.3324

​

Answer 1

Answer:

Modulation Index =0.8

Pc=124W

Power in sidebands may be calculated as =m

24

PP=0.8

2 × 4

124

=79.36W

Answer 2

Answer:

The modulation index of the AM signal, μ, measured is $0.447$.

Therefore, option a) $0.446$ is correct. ( closest to $0.447$ )

Explanation:

Data given,

The carrier power of an AM ( amplitude modulation ) signal, $P_{C}$ = $1kW$ = $1000W$

The sideband power of the AM signal, $P_{S}$ = $100W$

The AM signal's modulation index, μ =?

From the equation given below, we can find out the modulation index of the signal:

• $P_{S} = P_{C}\times \frac{\mu^{2} }{2}$
• μ = $\sqrt{\frac{2P_{S} }{P_{C} } }$

After putting the given values of sideband power and carrier power in the equation, we get:

• μ = $\sqrt{\frac{2\times100}{1000 }$
• μ = $\sqrt{\frac{1}{5}$
• μ = $\sqrt{0.2}$
• μ = $0.447$

Hence, the modulation index of the AM signal, μ = $0.447$.