Which of the following constitutes a spurious emission?
The correct answer is D: An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted. What constitutes a spurious emission is an emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted. Spurious emissions are unwanted emissions that don't carry information. For amateur radio operators, this is important for transmitter compliance. Understanding this helps ensure legal operation.
Exam Tip
Spurious emission = emission outside necessary bandwidth that can be reduced/eliminated without affecting information. Think 'S'purious 'E'mission = 'S'ignal 'E'xtra (unwanted). Spurious emissions are unwanted emissions that don't carry information. Not call sign violation, not intentional signal, not interference level - just unwanted emission outside bandwidth.
Memory Aid
"Spurious emission = emission outside necessary bandwidth that can be reduced/eliminated without affecting information. Think 'S'purious 'E'mission = 'S'ignal 'E'xtra. Spurious emissions are unwanted emissions that don't carry information. Important for transmitter compliance."
Real-World Application
A spurious emission: A transmitter produces a signal at 14.200 MHz (intended frequency) but also produces unwanted emissions at 14.400 MHz (harmonics or other spurious). The emission at 14.400 MHz is outside the necessary bandwidth and can be reduced or eliminated (with filters) without affecting the information transmitted. This is a spurious emission - unwanted emission outside necessary bandwidth.
FCC Part 97.307Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Transmission without proper call sign isn't a spurious emission - it's a rules violation, not an emission type. Call sign violation isn't spurious.
Option B: Incorrect. Signal to prevent detection isn't a spurious emission - it's intentional, not spurious. Intentional signal isn't spurious.
Option C: Incorrect. Signal interfering with another station exceeding 40 dB below fundamental isn't the definition - spurious emissions are defined by being outside necessary bandwidth, not by interference level. Interference level isn't the definition.
题目解析
The correct answer is D: An emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted. What constitutes a spurious emission is an emission outside the signal's necessary bandwidth that can be reduced or eliminated without affecting the information transmitted. Spurious emissions are unwanted emissions that don't carry information. For amateur radio operators, this is important for transmitter compliance. Understanding this helps ensure legal operation.
考试技巧
Spurious emission = emission outside necessary bandwidth that can be reduced/eliminated without affecting information. Think 'S'purious 'E'mission = 'S'ignal 'E'xtra (unwanted). Spurious emissions are unwanted emissions that don't carry information. Not call sign violation, not intentional signal, not interference level - just unwanted emission outside bandwidth.
记忆口诀
Spurious emission = emission outside necessary bandwidth that can be reduced/eliminated without affecting information. Think 'S'purious 'E'mission = 'S'ignal 'E'xtra. Spurious emissions are unwanted emissions that don't carry information. Important for transmitter compliance.
实际应用示例
A spurious emission: A transmitter produces a signal at 14.200 MHz (intended frequency) but also produces unwanted emissions at 14.400 MHz (harmonics or other spurious). The emission at 14.400 MHz is outside the necessary bandwidth and can be reduced or eliminated (with filters) without affecting the information transmitted. This is a spurious emission - unwanted emission outside necessary bandwidth.
错误选项分析
Option A: Incorrect. Transmission without proper call sign isn't a spurious emission - it's a rules violation, not an emission type. Call sign violation isn't spurious. Option B: Incorrect. Signal to prevent detection isn't a spurious emission - it's intentional, not spurious. Intentional signal isn't spurious. Option C: Incorrect. Signal interfering with another station exceeding 40 dB below fundamental isn't the definition - spurious emissions are defined by being outside necessary bandwidth, not by interference level. Interference level isn't the definition.
知识点
Spurious emission, Outside necessary bandwidth, Can be reduced or eliminated, Doesn't affect information
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.