Which of the following can be used to generate FM phone signals?
The correct answer is B: Reactance modulation of a local oscillator. Which of the following can be used to generate FM phone signals is reactance modulation of a local oscillator. Reactance modulation varies frequency for FM. For amateur radio operators, this is important for modulation. Understanding this helps when generating FM signals.
Exam Tip
Generate FM phone signals = reactance modulation of local oscillator. Think 'F'M = 'F'requency 'M'odulation (reactance modulation). Reactance modulation varies frequency for FM. Not balanced modulation, not final amplifier, not balanced modulation of oscillator - just reactance modulation of local oscillator.
Memory Aid
"Generate FM phone signals = reactance modulation of local oscillator. Think 'F'M = 'R'eactance 'M'odulation. Reactance modulation varies frequency for FM. Important for modulation."
Real-World Application
Generating FM phone signals: Reactance modulation of a local oscillator can be used. By varying the reactance in the oscillator circuit, the frequency is modulated. This is the method - reactance modulation of local oscillator.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Balanced modulation of audio amplifier isn't FM - reactance modulation of oscillator is FM. Balanced modulation isn't FM.
Option C: Incorrect. Reactance modulation of final amplifier isn't correct - reactance modulation of local oscillator is FM. Final amplifier isn't correct.
Option D: Incorrect. Balanced modulation of local oscillator isn't FM - reactance modulation is FM. Balanced modulation isn't FM.
题目解析
The correct answer is B: Reactance modulation of a local oscillator. Which of the following can be used to generate FM phone signals is reactance modulation of a local oscillator. Reactance modulation varies frequency for FM. For amateur radio operators, this is important for modulation. Understanding this helps when generating FM signals.
考试技巧
Generate FM phone signals = reactance modulation of local oscillator. Think 'F'M = 'F'requency 'M'odulation (reactance modulation). Reactance modulation varies frequency for FM. Not balanced modulation, not final amplifier, not balanced modulation of oscillator - just reactance modulation of local oscillator.
记忆口诀
Generate FM phone signals = reactance modulation of local oscillator. Think 'F'M = 'R'eactance 'M'odulation. Reactance modulation varies frequency for FM. Important for modulation.
实际应用示例
Generating FM phone signals: Reactance modulation of a local oscillator can be used. By varying the reactance in the oscillator circuit, the frequency is modulated. This is the method - reactance modulation of local oscillator.
错误选项分析
Option A: Incorrect. Balanced modulation of audio amplifier isn't FM - reactance modulation of oscillator is FM. Balanced modulation isn't FM. Option C: Incorrect. Reactance modulation of final amplifier isn't correct - reactance modulation of local oscillator is FM. Final amplifier isn't correct. Option D: Incorrect. Balanced modulation of local oscillator isn't FM - reactance modulation is FM. Balanced modulation isn't FM.
知识点
Generate FM phone signals, Reactance modulation, Local oscillator
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.