Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?
The correct answer is C: The input switching threshold is about half the power supply voltage. Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply is that the input switching threshold is about half the power supply voltage. This gives maximum noise margin. For amateur radio operators, this is important for digital circuits. Understanding this helps when using CMOS.
Exam Tip
CMOS noise immunity = input switching threshold about half power supply voltage. Think 'C'MOS 'N'oise 'I'mmunity = 'C'enter 'N'oise margin (half supply). This gives maximum noise margin. Not bypass capacitance, not twice supply, not bandwidth - just half supply threshold.
Memory Aid
"CMOS noise immunity = input switching threshold about half power supply voltage. Think 'C'MOS = 'H'alf supply threshold. This gives maximum noise margin. Important for digital circuits."
Real-World Application
CMOS digital integrated circuits have high immunity to noise: It's because the input switching threshold is about half the power supply voltage. This provides maximum noise margin - equal distance from both supply rails. This is the reason - half supply threshold.
Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Large bypass capacitance inherent isn't the reason - input threshold at half supply gives noise immunity. Bypass capacitance isn't the reason.
Option B: Incorrect. Input switching threshold about twice power supply voltage isn't correct - it's about half. Twice isn't correct.
Option D: Incorrect. Bandwidth very limited isn't the reason - input threshold at half supply gives noise immunity. Bandwidth isn't the reason.
题目解析
The correct answer is C: The input switching threshold is about half the power supply voltage. Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply is that the input switching threshold is about half the power supply voltage. This gives maximum noise margin. For amateur radio operators, this is important for digital circuits. Understanding this helps when using CMOS.
考试技巧
CMOS noise immunity = input switching threshold about half power supply voltage. Think 'C'MOS 'N'oise 'I'mmunity = 'C'enter 'N'oise margin (half supply). This gives maximum noise margin. Not bypass capacitance, not twice supply, not bandwidth - just half supply threshold.
记忆口诀
CMOS noise immunity = input switching threshold about half power supply voltage. Think 'C'MOS = 'H'alf supply threshold. This gives maximum noise margin. Important for digital circuits.
实际应用示例
CMOS digital integrated circuits have high immunity to noise: It's because the input switching threshold is about half the power supply voltage. This provides maximum noise margin - equal distance from both supply rails. This is the reason - half supply threshold.
错误选项分析
Option A: Incorrect. Large bypass capacitance inherent isn't the reason - input threshold at half supply gives noise immunity. Bypass capacitance isn't the reason. Option B: Incorrect. Input switching threshold about twice power supply voltage isn't correct - it's about half. Twice isn't correct. Option D: Incorrect. Bandwidth very limited isn't the reason - input threshold at half supply gives noise immunity. Bandwidth isn't the reason.
知识点
CMOS digital integrated circuits, High immunity to noise, Input signal or power supply, Input switching threshold, About half power supply voltage
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.