Which of the following is characteristic of QPSK31?
The correct answer is D: All these choices are correct. Characteristics of QPSK31 include: it is sideband sensitive, its encoding provides error correction, and its bandwidth is approximately the same as BPSK31. All three are QPSK31 characteristics. For amateur radio operators, this explains QPSK31 operation. Understanding this helps when operating QPSK31.
Exam Tip
All three are QPSK31 characteristics: sideband sensitive, error correction encoding, bandwidth same as BPSK31. When all listed characteristics apply to QPSK31, 'all of the above' is usually the answer. All are key QPSK31 features.
Memory Aid
"All three are QPSK31 characteristics: Sideband sensitive, Error correction encoding, Bandwidth same as BPSK31. Think 'A'll 'Q'PSK31 'C'haracteristics. All three are key QPSK31 features. Improved version of BPSK31."
Real-World Application
QPSK31 has: (1) Sideband sensitivity - must use correct sideband, (2) Error correction encoding - provides better error handling than BPSK31, (3) Bandwidth approximately same as BPSK31 - similar spectral efficiency. All three are characteristics of QPSK31. This makes QPSK31 an improved version of BPSK31.
Key Concepts
Why Other Options Are Wrong
Option A: While correct, this is incomplete. Error correction and bandwidth are also characteristics.
Option B: While correct, this is incomplete. Sideband sensitivity and bandwidth are also characteristics.
Option C: While correct, this is incomplete. Sideband sensitivity and error correction are also characteristics.
题目解析
The correct answer is D: All these choices are correct. Characteristics of QPSK31 include: it is sideband sensitive, its encoding provides error correction, and its bandwidth is approximately the same as BPSK31. All three are QPSK31 characteristics. For amateur radio operators, this explains QPSK31 operation. Understanding this helps when operating QPSK31.
考试技巧
All three are QPSK31 characteristics: sideband sensitive, error correction encoding, bandwidth same as BPSK31. When all listed characteristics apply to QPSK31, 'all of the above' is usually the answer. All are key QPSK31 features.
记忆口诀
All three are QPSK31 characteristics: Sideband sensitive, Error correction encoding, Bandwidth same as BPSK31. Think 'A'll 'Q'PSK31 'C'haracteristics. All three are key QPSK31 features. Improved version of BPSK31.
实际应用示例
QPSK31 has: (1) Sideband sensitivity - must use correct sideband, (2) Error correction encoding - provides better error handling than BPSK31, (3) Bandwidth approximately same as BPSK31 - similar spectral efficiency. All three are characteristics of QPSK31. This makes QPSK31 an improved version of BPSK31.
错误选项分析
Option A: While correct, this is incomplete. Error correction and bandwidth are also characteristics. Option B: While correct, this is incomplete. Sideband sensitivity and bandwidth are also characteristics. Option C: While correct, this is incomplete. Sideband sensitivity and error correction are also characteristics.
知识点
QPSK31, Sideband sensitive, Error correction, Bandwidth
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.