What causes interference received as a series of carriers at regular intervals across a wide frequency range?
The correct answer is A: Switch-mode power supplies. What causes interference received as a series of carriers at regular intervals across a wide frequency range is switch-mode power supplies. Switch-mode power supplies generate harmonics at regular intervals. For amateur radio operators, this is important for troubleshooting interference. Understanding this helps when identifying interference sources.
Exam Tip
Interference as carriers at regular intervals = switch-mode power supplies. Think 'S'witch-'M'ode 'P'ower 'S'upplies = 'S'eries of 'M'ultiple 'P'ower 'S'upply harmonics. Switch-mode power supplies generate harmonics at regular intervals. Not radar, not security cameras, not electric fences - just switch-mode power supplies.
Memory Aid
"Interference as carriers at regular intervals = switch-mode power supplies. Think 'S'witch-'M'ode = 'S'eries of 'M'ultiple harmonics. Switch-mode power supplies generate harmonics at regular intervals. Important for troubleshooting interference."
Real-World Application
Interference received as a series of carriers at regular intervals across a wide frequency range: It's caused by switch-mode power supplies. These power supplies switch at high frequencies and generate harmonics at regular intervals (multiples of the switching frequency). This is the cause - switch-mode power supplies.
Key Concepts
Why Other Options Are Wrong
Option B (Radar transmitters): Incorrect. Radar transmitters don't cause carriers at regular intervals - switch-mode power supplies do. Radar isn't the cause.
Option C (Wireless security camera transmitters): Incorrect. Security camera transmitters don't cause carriers at regular intervals - switch-mode power supplies do. Security cameras isn't the cause.
Option D (Electric fences): Incorrect. Electric fences don't cause carriers at regular intervals - switch-mode power supplies do. Electric fences isn't the cause.
题目解析
The correct answer is A: Switch-mode power supplies. What causes interference received as a series of carriers at regular intervals across a wide frequency range is switch-mode power supplies. Switch-mode power supplies generate harmonics at regular intervals. For amateur radio operators, this is important for troubleshooting interference. Understanding this helps when identifying interference sources.
考试技巧
Interference as carriers at regular intervals = switch-mode power supplies. Think 'S'witch-'M'ode 'P'ower 'S'upplies = 'S'eries of 'M'ultiple 'P'ower 'S'upply harmonics. Switch-mode power supplies generate harmonics at regular intervals. Not radar, not security cameras, not electric fences - just switch-mode power supplies.
记忆口诀
Interference as carriers at regular intervals = switch-mode power supplies. Think 'S'witch-'M'ode = 'S'eries of 'M'ultiple harmonics. Switch-mode power supplies generate harmonics at regular intervals. Important for troubleshooting interference.
实际应用示例
Interference received as a series of carriers at regular intervals across a wide frequency range: It's caused by switch-mode power supplies. These power supplies switch at high frequencies and generate harmonics at regular intervals (multiples of the switching frequency). This is the cause - switch-mode power supplies.
错误选项分析
Option B (Radar transmitters): Incorrect. Radar transmitters don't cause carriers at regular intervals - switch-mode power supplies do. Radar isn't the cause. Option C (Wireless security camera transmitters): Incorrect. Security camera transmitters don't cause carriers at regular intervals - switch-mode power supplies do. Security cameras isn't the cause. Option D (Electric fences): Incorrect. Electric fences don't cause carriers at regular intervals - switch-mode power supplies do. Electric fences isn't the cause.
知识点
Interference, Series of carriers at regular intervals, Wide frequency range, Switch-mode power supplies
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.