Which of the following receiver filter bandwidths provides the best signal-to-noise ratio for SSB reception?
The correct answer is C: 2400 Hz. For SSB reception, a receiver filter bandwidth of 2400 Hz (2.4 kHz) provides the best signal-to-noise ratio. This bandwidth is wide enough to pass the entire SSB signal (which is about 2.4 kHz wide) but narrow enough to reject adjacent signals and noise.
SSB signals occupy approximately 2.4 kHz of bandwidth. Using a 2.4 kHz filter matches the signal bandwidth, allowing the full signal through while rejecting noise and interference outside that bandwidth. Narrower filters (like 500 Hz or 1000 Hz) would cut off parts of the SSB signal, causing distortion. Wider filters (like 5000 Hz) would let in more noise and adjacent signals, reducing signal-to-noise ratio. 2.4 kHz is the 'sweet spot' for SSB.
Exam Tip
SSB bandwidth = 2400 Hz. Remember: For SSB reception, 2400 Hz (2.4 kHz) bandwidth provides the best signal-to-noise ratio. This matches the SSB signal width.
Memory Aid
"**S**SB **B**andwidth = **2**400 **H**z (think 'SB = 2400 Hz')"
Real-World Application
You're receiving an SSB signal on 20 meters. You select the 2400 Hz bandwidth filter on your transceiver. This filter is wide enough to pass the entire SSB signal (which is about 2.4 kHz wide) but narrow enough to reject adjacent signals and noise. The signal sounds clear with good signal-to-noise ratio. If you used a 500 Hz filter, the signal would be distorted. If you used 5000 Hz, you'd hear more noise.
FCC Part 97.3Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. 500 Hz is too narrow for SSB. SSB signals are about 2.4 kHz wide, so a 500 Hz filter would cut off most of the signal, causing severe distortion.
Option B: Incorrect. 1000 Hz is still too narrow for SSB. It would cut off parts of the SSB signal.
Option D: Incorrect. 5000 Hz is too wide for SSB. It would let in more noise and adjacent signals, reducing signal-to-noise ratio.
题目解析
The correct answer is C: 2400 Hz. For SSB reception, a receiver filter bandwidth of 2400 Hz (2.4 kHz) provides the best signal-to-noise ratio. This bandwidth is wide enough to pass the entire SSB signal (which is about 2.4 kHz wide) but narrow enough to reject adjacent signals and noise. SSB signals occupy approximately 2.4 kHz of bandwidth. Using a 2.4 kHz filter matches the signal bandwidth, allowing the full signal through while rejecting noise and interference outside that bandwidth. Narrower filters (like 500 Hz or 1000 Hz) would cut off parts of the SSB signal, causing distortion. Wider filters (like 5000 Hz) would let in more noise and adjacent signals, reducing signal-to-noise ratio. 2.4 kHz is the 'sweet spot' for SSB.
考试技巧
SSB bandwidth = 2400 Hz. Remember: For SSB reception, 2400 Hz (2.4 kHz) bandwidth provides the best signal-to-noise ratio. This matches the SSB signal width.
记忆口诀
**S**SB **B**andwidth = **2**400 **H**z (think 'SB = 2400 Hz')
实际应用示例
You're receiving an SSB signal on 20 meters. You select the 2400 Hz bandwidth filter on your transceiver. This filter is wide enough to pass the entire SSB signal (which is about 2.4 kHz wide) but narrow enough to reject adjacent signals and noise. The signal sounds clear with good signal-to-noise ratio. If you used a 500 Hz filter, the signal would be distorted. If you used 5000 Hz, you'd hear more noise.
错误选项分析
Option A: Incorrect. 500 Hz is too narrow for SSB. SSB signals are about 2.4 kHz wide, so a 500 Hz filter would cut off most of the signal, causing severe distortion. Option B: Incorrect. 1000 Hz is still too narrow for SSB. It would cut off parts of the SSB signal. Option D: Incorrect. 5000 Hz is too wide for SSB. It would let in more noise and adjacent signals, reducing signal-to-noise ratio.
知识点
SSB reception, Bandwidth, Signal-to-noise ratio, 2400 Hz
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.