What happens as a receiver’s noise reduction control level is increased?
The correct answer is A: Received signals may become distorted. What happens as a receiver's noise reduction control level is increased is that received signals may become distorted. Noise reduction processes the signal to reduce noise, but excessive noise reduction can distort the signal. For amateur radio operators, this is a trade-off - more noise reduction may mean more distortion. Understanding this helps when using noise reduction.
Exam Tip
Increased noise reduction = received signals may become distorted. Think 'N'oise 'R'eduction = 'N'oise 'R'educed but 'R'isk of distortion. Excessive noise reduction can distort signals. Not frequency instability, not CW attenuation, not frequency shift - just distortion.
Memory Aid
"Increased noise reduction = received signals may become distorted. Think 'N'oise 'R'eduction = 'N'oise 'R'educed but 'R'isk. Excessive noise reduction can distort signals. Trade-off between noise reduction and signal quality."
Real-World Application
You increase the noise reduction control to reduce background noise. At moderate levels, noise is reduced with minimal distortion. At high levels, the signal may become distorted as the noise reduction algorithm processes the signal too aggressively. There's a trade-off between noise reduction and signal quality.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Noise reduction doesn't make frequency unstable - it processes the signal, not the frequency. Frequency stability isn't affected.
Option C: Incorrect. Noise reduction doesn't severely attenuate CW signals - it may affect them, but severe attenuation isn't typical. Distortion is the main issue.
Option D: Incorrect. Noise reduction doesn't shift frequency - it processes the signal, not the frequency. Frequency shift isn't an effect.
题目解析
The correct answer is A: Received signals may become distorted. What happens as a receiver's noise reduction control level is increased is that received signals may become distorted. Noise reduction processes the signal to reduce noise, but excessive noise reduction can distort the signal. For amateur radio operators, this is a trade-off - more noise reduction may mean more distortion. Understanding this helps when using noise reduction.
考试技巧
Increased noise reduction = received signals may become distorted. Think 'N'oise 'R'eduction = 'N'oise 'R'educed but 'R'isk of distortion. Excessive noise reduction can distort signals. Not frequency instability, not CW attenuation, not frequency shift - just distortion.
记忆口诀
Increased noise reduction = received signals may become distorted. Think 'N'oise 'R'eduction = 'N'oise 'R'educed but 'R'isk. Excessive noise reduction can distort signals. Trade-off between noise reduction and signal quality.
实际应用示例
You increase the noise reduction control to reduce background noise. At moderate levels, noise is reduced with minimal distortion. At high levels, the signal may become distorted as the noise reduction algorithm processes the signal too aggressively. There's a trade-off between noise reduction and signal quality.
错误选项分析
Option B: Incorrect. Noise reduction doesn't make frequency unstable - it processes the signal, not the frequency. Frequency stability isn't affected. Option C: Incorrect. Noise reduction doesn't severely attenuate CW signals - it may affect them, but severe attenuation isn't typical. Distortion is the main issue. Option D: Incorrect. Noise reduction doesn't shift frequency - it processes the signal, not the frequency. Frequency shift isn't an effect.
知识点
Noise reduction, Signal distortion, Noise reduction control, Receiver features
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.