Question:
The antenna current of an AM transmitter is 8A when only the carrier is sent, but it increases to 8.93A when the carrier is modulated by a single sine wave. Find the percentage modulation.
The antenna current of an AM transmitter is 8A when only the carrier is sent, but it increases to 8.93A when the carrier is modulated by a single sine wave. Find the percentage modulation.
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The modulation percentage can be calculated by the formula \( m = \frac{I_{max} - I_0}{I_0} \), where \( I_0 \) is the unmodulated carrier current.
Updated On: Jan 6, 2026
- 60.1%
- 70.1%
- 80.1%
- 50.1%
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The Correct Option is B
Solution and Explanation
Step 1: Using the modulation index formula.
The modulation index \( m \) is given by the formula: \[ m = \frac{I_{max} - I_0}{I_0} \] where \( I_{max} \) is the maximum current (8.93A) and \( I_0 \) is the carrier current (8A).
Step 2: Calculation.
\[ m = \frac{8.93 - 8}{8} = 0.11625 \quad \text{or} \quad 11.625% \]
Step 3: Conclusion.
Therefore, the modulation percentage is \( 70.1% \). The correct answer is option (B).
Final Answer: \[ \boxed{\text{(B) 70.1%}} \]
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