Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store
seo-qna
SearchIcon
banner

What will be the modulation index of the AM wave shown in the figure:
seo images

Answer
VerifiedVerified
432.6k+ views
like imagedislike image
Hint: Learn the definition of AM wave. Study the definition of modulation index and its importance. Use the formula for modulation index for amplitude modulated wave to find the modulation index of the graph given.

Formula used:
The modulation index of a amplitude modulated wave is given by,
ma=VmaxVminVmax+Vmin
Where, ma is the modulation index of the wave Vmax is the maximum amplitude of the of the AM wave and Vminis the minimum amplitude of the AM wave.

Complete step by step answer:
We know that amplitude modulated is one type of modulated wave where the information is modulated into the amplitude of the carrier wave. The modulation factor of a wave decides how well a wave is modulated in the carrier signal. If the value of the modulation index is 1 the wave is said to be fully modulated.

Now, the value of modulation index for amplitude modulated wave is given by,
ma=VmaxVminVmax+Vmin
Now, here we can see from the graph that the maximum voltage amplitude Vmax=13V and the minimum voltage amplitude of the AM wave is Vmin=7V.
 Hence, putting the values we will have,
ma=13713+7
ma=620=310
ma=0.3

Hence, the modulation index of the given amplitude modulated wave is 0.3.

Note: The modulation index of any wave is a dimensionless quantity as it is the ratio of the voltages. The percentage modulation is the percentage of the modulation index in this case the modulation percentage is 0.3×100=30%. It represents that only 30% of the signal wave is modulated in the carrier wave.