Which of the following is an effect of overmodulation?
The correct answer is D: Excessive bandwidth. An effect of overmodulation is excessive bandwidth. Overmodulation causes the signal to extend beyond its intended bandwidth, creating interference. For amateur radio operators, this is why proper modulation levels are important. Understanding this helps when operating AM.
Exam Tip
Overmodulation effect = excessive bandwidth. Think 'O'vermodulation = 'O'verextends bandwidth. Overmodulation causes signal to extend beyond intended bandwidth, creating interference. Not insufficient audio, not insufficient bandwidth, not frequency drift - just excessive bandwidth.
Memory Aid
"Overmodulation effect = excessive bandwidth. Think 'O'vermodulation = 'O'verextends bandwidth. Overmodulation causes signal to extend beyond intended bandwidth, creating interference. Important to prevent overmodulation."
Real-World Application
You overmodulate an AM signal. The signal extends beyond its intended bandwidth, creating interference to adjacent frequencies. Overmodulation causes excessive bandwidth - the signal spreads out more than it should. This is why proper modulation levels are important - to prevent excessive bandwidth and interference.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Overmodulation doesn't cause insufficient audio - it causes too much modulation, not too little. Insufficient audio is from under-modulation.
Option B: Incorrect. Overmodulation doesn't cause insufficient bandwidth - it causes excessive bandwidth, not insufficient. Insufficient bandwidth is different.
Option C: Incorrect. Overmodulation doesn't cause frequency drift - frequency drift comes from oscillator instability, not modulation. Frequency drift is different.
题目解析
The correct answer is D: Excessive bandwidth. An effect of overmodulation is excessive bandwidth. Overmodulation causes the signal to extend beyond its intended bandwidth, creating interference. For amateur radio operators, this is why proper modulation levels are important. Understanding this helps when operating AM.
考试技巧
Overmodulation effect = excessive bandwidth. Think 'O'vermodulation = 'O'verextends bandwidth. Overmodulation causes signal to extend beyond intended bandwidth, creating interference. Not insufficient audio, not insufficient bandwidth, not frequency drift - just excessive bandwidth.
记忆口诀
Overmodulation effect = excessive bandwidth. Think 'O'vermodulation = 'O'verextends bandwidth. Overmodulation causes signal to extend beyond intended bandwidth, creating interference. Important to prevent overmodulation.
实际应用示例
You overmodulate an AM signal. The signal extends beyond its intended bandwidth, creating interference to adjacent frequencies. Overmodulation causes excessive bandwidth - the signal spreads out more than it should. This is why proper modulation levels are important - to prevent excessive bandwidth and interference.
错误选项分析
Option A: Incorrect. Overmodulation doesn't cause insufficient audio - it causes too much modulation, not too little. Insufficient audio is from under-modulation. Option B: Incorrect. Overmodulation doesn't cause insufficient bandwidth - it causes excessive bandwidth, not insufficient. Insufficient bandwidth is different. Option C: Incorrect. Overmodulation doesn't cause frequency drift - frequency drift comes from oscillator instability, not modulation. Frequency drift is different.
知识点
Overmodulation, Excessive bandwidth, Interference, Modulation levels
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.