Deep Dive: E7E05
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.
Why Other Answers 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.
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 Example
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.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E7E
Reference: 2024-2028 Question Pool · E7 - Practical Circuits
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E7E topic.