In FM system, if the depth of modulation is doubled, the output powera)Increase by factor of √2b)Increases by factor of √3c)Increases by factor of 2d)Remains at unmodulated valueCorrect answer is option 'D'. Can you explain this answer?

Question

In FM system, if the depth of modulation is doubled, the output powera)Increase by factor of &radic;2b)Increases by factor of &radic;3c)Increases by factor of 2d)Remains at unmodulated valueCorrect answer is option 'D'. Can you explain this answer?

Answer

Explanation:
Increasing the depth of modulation in an FM system refers to increasing the amplitude of the modulating signal. The depth of modulation is calculated as the ratio of the peak frequency deviation to the frequency of the modulating signal.

Effect on Output Power:
When the depth of modulation is doubled, it means that the amplitude of the modulating signal has increased. This results in a wider frequency deviation of the carrier signal, which in turn affects the output power of the FM system.

Output Power in FM System:
In an FM system, the output power is directly proportional to the square of the amplitude of the modulating signal. Therefore, when the depth of modulation is doubled, the output power does not increase by a factor of √2 or √3. Instead, it remains at the unmodulated value.

Conclusion:
In summary, doubling the depth of modulation in an FM system does not lead to a direct increase in the output power. The output power remains at the unmodulated value despite the increase in the amplitude of the modulating signal.

Answer

For a carrier signal, c(t)=A_ccos(2πf_ct) the corresponding FM signal power is

This is independent of depth of modulation. So output power of modulated FM is the same as unmodulated signal power.

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