ACtE08 · Chapter 8Demo2 · Set 2🏛️ Past Licensure QuestionID: 91b554a5

In Amplitude Modulation (AM), what happens to the total transmitted power as the modulation index ( $\mu$ ) is increased?

Multiple Choice Options

A
Total power increases
✓ Correct Option
B
Total power decreases
C
Total power remains constant
D
Total power fluctuates randomly

Detailed Technical Solution & Explanation

In Amplitude Modulation, the total transmitted power $P_t$ consists of the unmodulated carrier power $P_c$ plus the power contained in both sidebands ( $P_{USB} + P_{LSB}$ ):

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

Where $\mu$ is the modulation index ( $0 \le \mu \le 1$ ). Because carrier power $P_c$ remains constant while sideband power is directly proportional to $\mu^2$ , increasing the modulation index causes the total transmitted power to increase quadratically.

Option Analysis:

•

Option A (Total power increases): Correct;

P_t = P_c(1 + \mu^2/2)

, so power increases with increasing

\mu

•

Option B (Total power decreases): Incorrect; power increases with sideband energy.

•

Option C (Total power remains constant): Incorrect; in Frequency Modulation (FM), total power is constant, but in AM it increases.

•

Option D (Total power fluctuates randomly): Incorrect; power variation is deterministic.

Reference: Demo2 · Set 2NEC Licensure Syllabus

In Amplitude Modulation (AM), what happens to the total transmitted power as the modulation index ( $\mu$ ) is increased?

Multiple Choice Options

Detailed Technical Solution & Explanation

Option Analysis:

Want to practice this topic interactively?

In Amplitude Modulation (AM), what happens to the total transmitted power as the modulation index ( $\mu$ ) is increased?

Multiple Choice Options

Detailed Technical Solution & Explanation

Option Analysis:

Want to practice this topic interactively?