Which of the following describes a linear amplifier?
The correct answer is B: An amplifier in which the output preserves the input waveform. What describes a linear amplifier is an amplifier in which the output preserves the input waveform. Linear amplifiers reproduce the input signal without distortion, maintaining the waveform shape. For amateur radio operators, this is essential for SSB and AM. Understanding this helps when selecting amplifiers.
Exam Tip
Linear amplifier = output preserves input waveform. Think 'L'inear = 'L'ooks like input (preserves waveform). Linear amplifiers reproduce input signal without distortion, maintaining waveform shape. Not any RF amplifier, not Class C, not multiplier - just preserves waveform.
Memory Aid
"Linear amplifier = output preserves input waveform. Think 'L'inear = 'L'ooks like input. Linear amplifiers reproduce input signal without distortion, maintaining waveform shape. Essential for SSB and AM."
Real-World Application
A linear amplifier for SSB: The input SSB signal has a specific waveform. The linear amplifier amplifies it while preserving the exact waveform shape - no distortion. This is essential for SSB and AM, where the waveform contains the information. Class C amplifiers can't do this - they're non-linear.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Linear amplifier isn't any RF power amplifier used with a transceiver - Class C amplifiers are RF power amplifiers but aren't linear. Not all RF amplifiers are linear.
Option C: Incorrect. Linear amplifier isn't a Class C high efficiency amplifier - Class C is non-linear and only for constant-envelope signals. Class C isn't linear.
Option D: Incorrect. Linear amplifier isn't an amplifier used as a frequency multiplier - multipliers are non-linear. Multipliers aren't linear amplifiers.
题目解析
The correct answer is B: An amplifier in which the output preserves the input waveform. What describes a linear amplifier is an amplifier in which the output preserves the input waveform. Linear amplifiers reproduce the input signal without distortion, maintaining the waveform shape. For amateur radio operators, this is essential for SSB and AM. Understanding this helps when selecting amplifiers.
考试技巧
Linear amplifier = output preserves input waveform. Think 'L'inear = 'L'ooks like input (preserves waveform). Linear amplifiers reproduce input signal without distortion, maintaining waveform shape. Not any RF amplifier, not Class C, not multiplier - just preserves waveform.
记忆口诀
Linear amplifier = output preserves input waveform. Think 'L'inear = 'L'ooks like input. Linear amplifiers reproduce input signal without distortion, maintaining waveform shape. Essential for SSB and AM.
实际应用示例
A linear amplifier for SSB: The input SSB signal has a specific waveform. The linear amplifier amplifies it while preserving the exact waveform shape - no distortion. This is essential for SSB and AM, where the waveform contains the information. Class C amplifiers can't do this - they're non-linear.
错误选项分析
Option A: Incorrect. Linear amplifier isn't any RF power amplifier used with a transceiver - Class C amplifiers are RF power amplifiers but aren't linear. Not all RF amplifiers are linear. Option C: Incorrect. Linear amplifier isn't a Class C high efficiency amplifier - Class C is non-linear and only for constant-envelope signals. Class C isn't linear. Option D: Incorrect. Linear amplifier isn't an amplifier used as a frequency multiplier - multipliers are non-linear. Multipliers aren't linear amplifiers.
知识点
Linear amplifier, Output preserves input waveform, No distortion, Amplifier types
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.