Which of the following statements is true about PSK31?
The correct answer is B: Upper case letters use longer Varicode bit sequences and thus slow down transmission. A true statement about PSK31 is that upper case letters use longer Varicode bit sequences and thus slow down transmission. PSK31's Varicode assigns shorter codes to common characters (lower case) and longer codes to less common characters (upper case). For amateur radio operators, this explains PSK31 efficiency. Understanding this helps when operating PSK31.
Exam Tip
PSK31 upper case = longer Varicode sequences slow transmission. Think 'U'pper 'C'ase = 'U'se 'C'omplex (longer) codes. PSK31's Varicode assigns longer codes to upper case, slowing transmission. Not more power, not error correction, not higher power needed - just longer codes slow transmission.
Memory Aid
"PSK31 upper case = longer Varicode sequences slow transmission. Think 'U'pper 'C'ase = 'U'se 'C'omplex codes. PSK31's Varicode assigns longer codes to upper case, slowing transmission. Lower case is faster."
Real-World Application
PSK31 uses Varicode: Lower case 'e' has a short code (common character), upper case 'E' has a longer code (less common). When you type in upper case, PSK31 uses longer Varicode sequences, which takes more time to transmit, slowing down the transmission. This is why lower case is preferred in PSK31 - it's faster.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Upper case letters aren't sent with more power - power is constant, not character-dependent. Power isn't the issue.
Option C: Incorrect. PSK31 doesn't use error correction - it's a simple mode without error correction. Error correction isn't used.
Option D: Incorrect. PSK31 doesn't need higher power than RTTY - PSK31 is actually more efficient, not less. Higher power isn't needed.
题目解析
The correct answer is B: Upper case letters use longer Varicode bit sequences and thus slow down transmission. A true statement about PSK31 is that upper case letters use longer Varicode bit sequences and thus slow down transmission. PSK31's Varicode assigns shorter codes to common characters (lower case) and longer codes to less common characters (upper case). For amateur radio operators, this explains PSK31 efficiency. Understanding this helps when operating PSK31.
考试技巧
PSK31 upper case = longer Varicode sequences slow transmission. Think 'U'pper 'C'ase = 'U'se 'C'omplex (longer) codes. PSK31's Varicode assigns longer codes to upper case, slowing transmission. Not more power, not error correction, not higher power needed - just longer codes slow transmission.
记忆口诀
PSK31 upper case = longer Varicode sequences slow transmission. Think 'U'pper 'C'ase = 'U'se 'C'omplex codes. PSK31's Varicode assigns longer codes to upper case, slowing transmission. Lower case is faster.
实际应用示例
PSK31 uses Varicode: Lower case 'e' has a short code (common character), upper case 'E' has a longer code (less common). When you type in upper case, PSK31 uses longer Varicode sequences, which takes more time to transmit, slowing down the transmission. This is why lower case is preferred in PSK31 - it's faster.
错误选项分析
Option A: Incorrect. Upper case letters aren't sent with more power - power is constant, not character-dependent. Power isn't the issue. Option C: Incorrect. PSK31 doesn't use error correction - it's a simple mode without error correction. Error correction isn't used. Option D: Incorrect. PSK31 doesn't need higher power than RTTY - PSK31 is actually more efficient, not less. Higher power isn't needed.
知识点
PSK31, Upper case letters, Varicode, Longer bit sequences
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.