Question

Assertion :The AM modulation index is a measure based on the ratio of the modulation excursions of the RF signal to the level of the unmodulated carrier. Reason: Modulation is needed because further processing may not affect original wave

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

The amplitude modulation, AM, modulation index can be defined as the measure of extent of amplitude variation about an un-modulated carrier. The modulation index for amplitude modulation, AM, indicates the amount by which the modulated carrier varies around its static un-modulated level.

When expressed as a percentage it is the same as the depth of modulation. In other words it can be expressed as:

$m=\frac{M}{A}$

where, M is the modulation amplitude and is the peak change in the RF amplitude from its unmodulated value.and A is the carrier amplitude.

Modulation is needed because of the smooth transmission of message signal and further processing may not affect original wave.