ACtE08 · Chapter 8Demo2 · Set 2🏛️ Past Licensure QuestionID: 9c3db038

In Amplitude Modulation (AM), how does the total transmitted power vary with the modulation index ( $\mu$ )?

Multiple Choice Options

A
Power increases with the square of the modulation index
✓ Correct Option
B
Power decreases exponentially
C
Power remains constant regardless of modulation index
D
Power decreases linearly

Detailed Technical Solution & Explanation

In standard double-sideband full-carrier AM (DSB-FC), total power is expressed as:

P_t = P_c \left(1 + \frac{\mu^2}{2}\right) = P_c + \frac{1}{2} P_c \mu^2

Where $P_c$ is the unmodulated carrier power. Because carrier power is independent of $\mu$ , the additional power resides in the sidebands and increases in direct proportion to $\mu^2$ (parabolic / quadratic increase with modulation index).

Option Analysis:

•

Option A (Power increases with the square of the modulation index): Correct; sideband power is proportional to

\mu^2

•

Option B (Power decreases exponentially): Incorrect; power never decreases with modulation.

•

Option C (Power remains constant regardless of modulation index): Incorrect; true for FM, but false for AM.

•

Option D (Power decreases linearly): Incorrect.

Reference: Demo2 · Set 2NEC Licensure Syllabus

In Amplitude Modulation (AM), how does the total transmitted power vary with the modulation index ( $\mu$ )?

Multiple Choice Options

Detailed Technical Solution & Explanation

Option Analysis:

Want to practice this topic interactively?

In Amplitude Modulation (AM), how does the total transmitted power vary with the modulation index ( $\mu$ )?

Multiple Choice Options

Detailed Technical Solution & Explanation

Option Analysis:

Want to practice this topic interactively?