What is the difference between direct FSK and audio FSK?
The correct answer is A: Direct FSK modulates the transmitter VFO. What is the difference between direct FSK and audio FSK is that direct FSK modulates the transmitter VFO. Direct FSK directly changes the VFO frequency, while audio FSK modulates an audio tone. For amateur radio operators, this is important for understanding FSK implementation. Understanding this helps when using FSK modes.
Exam Tip
Direct FSK vs audio FSK = direct FSK modulates transmitter VFO. Think 'D'irect 'F'SK = 'D'irectly 'F'requency shifts VFO. Direct FSK directly changes the VFO frequency, while audio FSK modulates an audio tone. Not less bandwidth, not higher baud rates - just VFO modulation.
Memory Aid
"Direct FSK vs audio FSK = direct FSK modulates transmitter VFO. Think 'D'irect 'F'SK = 'V'FO modulation. Direct FSK directly changes the VFO frequency, while audio FSK modulates an audio tone. Important for understanding FSK implementation."
Real-World Application
Direct FSK vs audio FSK: Direct FSK modulates the transmitter VFO (Voltage-Controlled Oscillator) directly, changing the frequency. Audio FSK modulates an audio tone that's then fed into the microphone input. The key difference is that direct FSK modulates the VFO directly. This is the difference - direct FSK modulates the transmitter VFO.
Key Concepts
Why Other Options Are Wrong
Option B: Incorrect. Direct FSK doesn't necessarily occupy less bandwidth - the difference is how it's implemented, not bandwidth. Less bandwidth isn't the difference.
Option C: Incorrect. Direct FSK doesn't necessarily transmit higher baud rates - the difference is how it's implemented, not baud rate. Higher baud rates isn't the difference.
Option D: Incorrect. Since B and C are not correct, 'all of the above' cannot be correct. Only VFO modulation is the difference.
题目解析
The correct answer is A: Direct FSK modulates the transmitter VFO. What is the difference between direct FSK and audio FSK is that direct FSK modulates the transmitter VFO. Direct FSK directly changes the VFO frequency, while audio FSK modulates an audio tone. For amateur radio operators, this is important for understanding FSK implementation. Understanding this helps when using FSK modes.
考试技巧
Direct FSK vs audio FSK = direct FSK modulates transmitter VFO. Think 'D'irect 'F'SK = 'D'irectly 'F'requency shifts VFO. Direct FSK directly changes the VFO frequency, while audio FSK modulates an audio tone. Not less bandwidth, not higher baud rates - just VFO modulation.
记忆口诀
Direct FSK vs audio FSK = direct FSK modulates transmitter VFO. Think 'D'irect 'F'SK = 'V'FO modulation. Direct FSK directly changes the VFO frequency, while audio FSK modulates an audio tone. Important for understanding FSK implementation.
实际应用示例
Direct FSK vs audio FSK: Direct FSK modulates the transmitter VFO (Voltage-Controlled Oscillator) directly, changing the frequency. Audio FSK modulates an audio tone that's then fed into the microphone input. The key difference is that direct FSK modulates the VFO directly. This is the difference - direct FSK modulates the transmitter VFO.
错误选项分析
Option B: Incorrect. Direct FSK doesn't necessarily occupy less bandwidth - the difference is how it's implemented, not bandwidth. Less bandwidth isn't the difference. Option C: Incorrect. Direct FSK doesn't necessarily transmit higher baud rates - the difference is how it's implemented, not baud rate. Higher baud rates isn't the difference. Option D: Incorrect. Since B and C are not correct, 'all of the above' cannot be correct. Only VFO modulation is the difference.
知识点
Direct FSK, Audio FSK, Modulates transmitter VFO, FSK implementation
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.