What is the approximate bandwidth of a typical single sideband (SSB) voice signal?
The correct answer is B: 3 kHz. The approximate bandwidth of a typical single sideband (SSB) voice signal is 3 kHz. This bandwidth accommodates the audio frequencies needed for intelligible voice (typically 300-3000 Hz), plus some guard bands. SSB's narrow bandwidth is one of its main advantages, making it spectrum-efficient and good for weak-signal work. For amateur radio operators, understanding SSB bandwidth helps explain why multiple SSB signals can operate in a small frequency range and why SSB is preferred for weak-signal and DX work where spectrum efficiency matters.
Exam Tip
SSB bandwidth = 3 kHz. Think 'S'SB = 'S'ingle sideband = 'S'mall bandwidth (~3 kHz). Narrow enough for efficiency, wide enough for voice. 1 kHz is too narrow, 6-15 kHz is too wide.
Memory Aid
"SSB bandwidth = 3 kHz. Think 'S'SB = 'S'ingle sideband = 'S'mall bandwidth (~3 kHz). Narrow and efficient for voice communications. Standard for HF SSB operation."
Real-World Application
Your SSB signal on 20 meters uses about 3 kHz of bandwidth. This narrow bandwidth allows many SSB stations to operate in a small frequency range - you might have stations every 3-4 kHz. Compare this to FM, which needs 15 kHz per station. The 3 kHz bandwidth carries all the audio frequencies needed for clear voice communication.
Key Concepts
Why Other Options Are Wrong
Option A (1 kHz): Incorrect. 1 kHz is too narrow for voice - it would cut off important audio frequencies, making speech unintelligible. SSB needs about 3 kHz for good voice quality.
Option C (6 kHz): Incorrect. 6 kHz is wider than typical SSB - that's more like AM bandwidth. SSB uses about 3 kHz because it only transmits one sideband.
Option D (15 kHz): Incorrect. 15 kHz is FM bandwidth, not SSB. SSB is much narrower at about 3 kHz.
题目解析
The correct answer is B: 3 kHz. The approximate bandwidth of a typical single sideband (SSB) voice signal is 3 kHz. This bandwidth accommodates the audio frequencies needed for intelligible voice (typically 300-3000 Hz), plus some guard bands. SSB's narrow bandwidth is one of its main advantages, making it spectrum-efficient and good for weak-signal work. For amateur radio operators, understanding SSB bandwidth helps explain why multiple SSB signals can operate in a small frequency range and why SSB is preferred for weak-signal and DX work where spectrum efficiency matters.
考试技巧
SSB bandwidth = 3 kHz. Think 'S'SB = 'S'ingle sideband = 'S'mall bandwidth (~3 kHz). Narrow enough for efficiency, wide enough for voice. 1 kHz is too narrow, 6-15 kHz is too wide.
记忆口诀
SSB bandwidth = 3 kHz. Think 'S'SB = 'S'ingle sideband = 'S'mall bandwidth (~3 kHz). Narrow and efficient for voice communications. Standard for HF SSB operation.
实际应用示例
Your SSB signal on 20 meters uses about 3 kHz of bandwidth. This narrow bandwidth allows many SSB stations to operate in a small frequency range - you might have stations every 3-4 kHz. Compare this to FM, which needs 15 kHz per station. The 3 kHz bandwidth carries all the audio frequencies needed for clear voice communication.
错误选项分析
Option A (1 kHz): Incorrect. 1 kHz is too narrow for voice - it would cut off important audio frequencies, making speech unintelligible. SSB needs about 3 kHz for good voice quality. Option C (6 kHz): Incorrect. 6 kHz is wider than typical SSB - that's more like AM bandwidth. SSB uses about 3 kHz because it only transmits one sideband. Option D (15 kHz): Incorrect. 15 kHz is FM bandwidth, not SSB. SSB is much narrower at about 3 kHz.
知识点
SSB bandwidth, Single sideband, Voice bandwidth, Spectrum efficiency
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.