What is the ratio of PEP to average power for an unmodulated carrier?
The correct answer is B: 1.00. The ratio of PEP to average power for an unmodulated carrier is 1.00 (1:1). An unmodulated carrier has constant power, so PEP equals average power. For amateur radio operators, this is a fundamental relationship. Understanding this helps when calculating power for different modes.
Exam Tip
Unmodulated carrier PEP/average = 1.00. Think 'U'nmodulated 'C'arrier = 'U'niform 'C'onstant power = '1':1 ratio. Unmodulated carrier has constant power, so PEP equals average power. Not 0.707, not 1.414, not 2.00 - just 1.00.
Memory Aid
"Unmodulated carrier PEP/average = 1.00. Think 'U'nmodulated 'C'arrier = 'U'niform 'C'onstant = '1':1. Unmodulated carrier has constant power, so PEP equals average power. Ratio is 1.00."
Real-World Application
An unmodulated carrier transmits constant power (e.g., 100 watts). PEP = 100 watts, average power = 100 watts. The ratio is 1.00 (1:1). For modulated signals, PEP is higher than average, but for unmodulated carrier, they're equal.
Key Concepts
Why Other Options Are Wrong
Option A (0.707): Incorrect. 0.707 is the ratio of RMS to peak voltage (1/√2), not PEP to average for unmodulated carrier. That's a voltage ratio, not power ratio.
Option C (1.414): Incorrect. 1.414 is the ratio of peak to RMS voltage (√2), not PEP to average for unmodulated carrier. That's a voltage ratio, not power ratio.
Option D (2.00): Incorrect. 2.00 would be for some modulated signals, not unmodulated carrier. Unmodulated carrier has 1:1 ratio.
题目解析
The correct answer is B: 1.00. The ratio of PEP to average power for an unmodulated carrier is 1.00 (1:1). An unmodulated carrier has constant power, so PEP equals average power. For amateur radio operators, this is a fundamental relationship. Understanding this helps when calculating power for different modes.
考试技巧
Unmodulated carrier PEP/average = 1.00. Think 'U'nmodulated 'C'arrier = 'U'niform 'C'onstant power = '1':1 ratio. Unmodulated carrier has constant power, so PEP equals average power. Not 0.707, not 1.414, not 2.00 - just 1.00.
记忆口诀
Unmodulated carrier PEP/average = 1.00. Think 'U'nmodulated 'C'arrier = 'U'niform 'C'onstant = '1':1. Unmodulated carrier has constant power, so PEP equals average power. Ratio is 1.00.
实际应用示例
An unmodulated carrier transmits constant power (e.g., 100 watts). PEP = 100 watts, average power = 100 watts. The ratio is 1.00 (1:1). For modulated signals, PEP is higher than average, but for unmodulated carrier, they're equal.
错误选项分析
Option A (0.707): Incorrect. 0.707 is the ratio of RMS to peak voltage (1/√2), not PEP to average for unmodulated carrier. That's a voltage ratio, not power ratio. Option C (1.414): Incorrect. 1.414 is the ratio of peak to RMS voltage (√2), not PEP to average for unmodulated carrier. That's a voltage ratio, not power ratio. Option D (2.00): Incorrect. 2.00 would be for some modulated signals, not unmodulated carrier. Unmodulated carrier has 1:1 ratio.
知识点
PEP to average power, Unmodulated carrier, 1.00 ratio, Constant power
Verified Content
Question from official FCC General Class question pool. Explanation reviewed by licensed amateur radio operators.