What is added to an FM speech channel to boost the higher audio frequencies?
The correct answer is D: A pre-emphasis network. What is added to an FM speech channel to boost the higher audio frequencies is a pre-emphasis network. Pre-emphasis boosts high frequencies before transmission. For amateur radio operators, this is important for FM systems. Understanding this helps when working with FM.
Exam Tip
Added to FM speech channel to boost high frequencies = pre-emphasis network. Think 'P're-'E'mphasis = 'P're-'E'nhances high frequencies. Pre-emphasis boosts high frequencies before transmission. Not de-emphasis (reduces), not harmonic enhancer, not heterodyne enhancer - just pre-emphasis network.
Memory Aid
"Added to FM speech channel to boost high frequencies = pre-emphasis network. Think 'P're-'E'mphasis = 'B'oosts high frequencies. Pre-emphasis boosts high frequencies before transmission. Important for FM systems."
Real-World Application
Added to an FM speech channel to boost the higher audio frequencies: A pre-emphasis network is used. Pre-emphasis boosts high frequencies before transmission to improve signal-to-noise ratio. This is what's added - pre-emphasis network.
Key Concepts
Why Other Options Are Wrong
Option A (De-emphasis network): Incorrect. De-emphasis reduces high frequencies, doesn't boost - pre-emphasis boosts. De-emphasis isn't the answer.
Option B (Harmonic enhancer): Incorrect. Harmonic enhancer isn't used - pre-emphasis network boosts high frequencies. Harmonic enhancer isn't the answer.
Option C (Heterodyne enhancer): Incorrect. Heterodyne enhancer isn't used - pre-emphasis network boosts high frequencies. Heterodyne enhancer isn't the answer.
题目解析
The correct answer is D: A pre-emphasis network. What is added to an FM speech channel to boost the higher audio frequencies is a pre-emphasis network. Pre-emphasis boosts high frequencies before transmission. For amateur radio operators, this is important for FM systems. Understanding this helps when working with FM.
考试技巧
Added to FM speech channel to boost high frequencies = pre-emphasis network. Think 'P're-'E'mphasis = 'P're-'E'nhances high frequencies. Pre-emphasis boosts high frequencies before transmission. Not de-emphasis (reduces), not harmonic enhancer, not heterodyne enhancer - just pre-emphasis network.
记忆口诀
Added to FM speech channel to boost high frequencies = pre-emphasis network. Think 'P're-'E'mphasis = 'B'oosts high frequencies. Pre-emphasis boosts high frequencies before transmission. Important for FM systems.
实际应用示例
Added to an FM speech channel to boost the higher audio frequencies: A pre-emphasis network is used. Pre-emphasis boosts high frequencies before transmission to improve signal-to-noise ratio. This is what's added - pre-emphasis network.
错误选项分析
Option A (De-emphasis network): Incorrect. De-emphasis reduces high frequencies, doesn't boost - pre-emphasis boosts. De-emphasis isn't the answer. Option B (Harmonic enhancer): Incorrect. Harmonic enhancer isn't used - pre-emphasis network boosts high frequencies. Harmonic enhancer isn't the answer. Option C (Heterodyne enhancer): Incorrect. Heterodyne enhancer isn't used - pre-emphasis network boosts high frequencies. Heterodyne enhancer isn't the answer.
知识点
Added to FM speech channel, Boost higher audio frequencies, Pre-emphasis network
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.