What emission is produced by a reactance modulator connected to a transmitter RF amplifier stage?
The correct answer is B: Phase modulation. The emission produced by a reactance modulator connected to a transmitter RF amplifier stage is phase modulation. Reactance modulators vary the phase of the oscillator, producing phase modulation. For amateur radio operators, this is how phase modulation is generated. Understanding this helps when designing modulators.
Exam Tip
Reactance modulator output = phase modulation. Think 'R'eactance 'M'odulator = 'R'egulates 'M'odulation by varying 'P'hase. Reactance modulators vary oscillator phase, producing phase modulation. Not multiplex, not AM, not pulse - just phase modulation.
Memory Aid
"Reactance modulator output = phase modulation. Think 'R'eactance 'M'odulator = 'P'hase 'M'odulation. Reactance modulators vary oscillator phase, producing phase modulation. Standard phase modulation method."
Real-World Application
A reactance modulator: It varies the reactance (capacitance or inductance) in the oscillator circuit, which changes the oscillator's phase. This phase variation produces phase modulation. Reactance modulators are used to generate phase modulation in transmitters. This is how phase modulation is created.
Key Concepts
Why Other Options Are Wrong
Option A (Multiplex modulation): Incorrect. Reactance modulators don't produce multiplex modulation - they produce phase modulation. Multiplex is different.
Option C (Amplitude modulation): Incorrect. Reactance modulators don't produce amplitude modulation - they vary phase, not amplitude. AM is different.
Option D (Pulse modulation): Incorrect. Reactance modulators don't produce pulse modulation - they produce continuous phase modulation, not pulses. Pulse modulation is different.
题目解析
The correct answer is B: Phase modulation. The emission produced by a reactance modulator connected to a transmitter RF amplifier stage is phase modulation. Reactance modulators vary the phase of the oscillator, producing phase modulation. For amateur radio operators, this is how phase modulation is generated. Understanding this helps when designing modulators.
考试技巧
Reactance modulator output = phase modulation. Think 'R'eactance 'M'odulator = 'R'egulates 'M'odulation by varying 'P'hase. Reactance modulators vary oscillator phase, producing phase modulation. Not multiplex, not AM, not pulse - just phase modulation.
记忆口诀
Reactance modulator output = phase modulation. Think 'R'eactance 'M'odulator = 'P'hase 'M'odulation. Reactance modulators vary oscillator phase, producing phase modulation. Standard phase modulation method.
实际应用示例
A reactance modulator: It varies the reactance (capacitance or inductance) in the oscillator circuit, which changes the oscillator's phase. This phase variation produces phase modulation. Reactance modulators are used to generate phase modulation in transmitters. This is how phase modulation is created.
错误选项分析
Option A (Multiplex modulation): Incorrect. Reactance modulators don't produce multiplex modulation - they produce phase modulation. Multiplex is different. Option C (Amplitude modulation): Incorrect. Reactance modulators don't produce amplitude modulation - they vary phase, not amplitude. AM is different. Option D (Pulse modulation): Incorrect. Reactance modulators don't produce pulse modulation - they produce continuous phase modulation, not pulses. Pulse modulation is different.
知识点
Reactance modulator, Phase modulation, RF amplifier stage, Modulator types
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.