What does a third-order intercept level of 40 dBm mean with respect to receiver performance?
The correct answer is C: A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals. What does a third-order intercept level of 40 dBm mean with respect to receiver performance is that a pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals. Third-order intercept is where IMD product equals input signal level. For amateur radio operators, this is important for receiver performance. Understanding this helps when evaluating receivers.
Exam Tip
Third-order intercept 40 dBm = pair of 40 dBm input signals generates third-order IMD product with same amplitude as input signals. Think 'T'hird-'O'rder 'I'ntercept = 'T'heoretical 'O'utput 'I'ntersection (IMD = input). Third-order intercept is where IMD product equals input signal level. Not less than 40 dBm, not 40 dB above noise, not 1 mW with 40 dB - just 40 dBm where IMD equals input.
Memory Aid
"Third-order intercept 40 dBm = pair of 40 dBm input signals generates third-order IMD product with same amplitude as input signals. Think 'T'hird-'O'rder 'I'ntercept = 'I'MD equals input. Third-order intercept is where IMD product equals input signal level. Important for receiver performance."
Real-World Application
A third-order intercept level of 40 dBm: It means that a pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals. This is the intercept point - where IMD product equals input level. This is what it means - 40 dBm where IMD equals input.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Signals less than 40 dBm not generating audible IMD isn't the meaning - third-order intercept is where IMD equals input level. Less than 40 dBm isn't the meaning.
Option B: Incorrect. Receiver tolerating signals up to 40 dB above noise floor isn't the meaning - third-order intercept is where IMD equals input level. 40 dB above noise floor isn't the meaning.
Option D: Incorrect. Pair of 1 mW signals producing IMD 40 dB stronger isn't the meaning - third-order intercept is where IMD equals input level. 1 mW with 40 dB stronger isn't the meaning.
题目解析
The correct answer is C: A pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals. What does a third-order intercept level of 40 dBm mean with respect to receiver performance is that a pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals. Third-order intercept is where IMD product equals input signal level. For amateur radio operators, this is important for receiver performance. Understanding this helps when evaluating receivers.
考试技巧
Third-order intercept 40 dBm = pair of 40 dBm input signals generates third-order IMD product with same amplitude as input signals. Think 'T'hird-'O'rder 'I'ntercept = 'T'heoretical 'O'utput 'I'ntersection (IMD = input). Third-order intercept is where IMD product equals input signal level. Not less than 40 dBm, not 40 dB above noise, not 1 mW with 40 dB - just 40 dBm where IMD equals input.
记忆口诀
Third-order intercept 40 dBm = pair of 40 dBm input signals generates third-order IMD product with same amplitude as input signals. Think 'T'hird-'O'rder 'I'ntercept = 'I'MD equals input. Third-order intercept is where IMD product equals input signal level. Important for receiver performance.
实际应用示例
A third-order intercept level of 40 dBm: It means that a pair of 40 dBm input signals will theoretically generate a third-order intermodulation product that has the same output amplitude as either of the input signals. This is the intercept point - where IMD product equals input level. This is what it means - 40 dBm where IMD equals input.
错误选项分析
Option A: Incorrect. Signals less than 40 dBm not generating audible IMD isn't the meaning - third-order intercept is where IMD equals input level. Less than 40 dBm isn't the meaning. Option B: Incorrect. Receiver tolerating signals up to 40 dB above noise floor isn't the meaning - third-order intercept is where IMD equals input level. 40 dB above noise floor isn't the meaning. Option D: Incorrect. Pair of 1 mW signals producing IMD 40 dB stronger isn't the meaning - third-order intercept is where IMD equals input level. 1 mW with 40 dB stronger isn't the meaning.
知识点
Third-order intercept level, 40 dBm, Receiver performance, Pair of input signals, Third-order intermodulation product, Same output amplitude
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.