Deep Dive: E7F09
The correct answer is A: It removes high-frequency signal components that would otherwise be reproduced as lower frequency components. Why is an anti-aliasing filter required in a decimator is that it removes high-frequency signal components that would otherwise be reproduced as lower frequency components. Anti-aliasing prevents aliasing when reducing sample rate. For amateur radio operators, this is important for digital signal processing. Understanding this helps when working with decimators.
Why Other Answers Are Wrong
Option B: Incorrect. Peaking response of decimator isn't the reason - anti-aliasing removes high frequencies to prevent aliasing. Peaking response isn't the reason. Option C: Incorrect. Removing low-frequency components to eliminate DC restoration isn't the reason - anti-aliasing removes high frequencies to prevent aliasing. Low-frequency removal isn't the reason. Option D: Incorrect. Notching out sampling frequency isn't the reason - anti-aliasing removes high frequencies to prevent aliasing. Notching sampling frequency isn't the reason.
Exam Tip
Anti-aliasing filter in decimator = removes high-frequency components that would be reproduced as lower frequencies. Think 'A'nti-'A'liasing = 'A'voids 'A'liasing (removes high frequencies). Anti-aliasing prevents aliasing when reducing sample rate. Not peaking response, not low-frequency removal, not notching sampling frequency - just removes high frequencies to prevent aliasing.
Memory Aid
Anti-aliasing filter in decimator = removes high-frequency components that would be reproduced as lower frequencies. Think 'A'nti-'A'liasing = 'P'revents aliasing. Anti-aliasing prevents aliasing when reducing sample rate. Important for digital signal processing.
Real-World Example
An anti-aliasing filter required in a decimator: It removes high-frequency signal components that would otherwise be reproduced as lower frequency components. Without the filter, aliasing would occur when the sample rate is reduced. This is the reason - prevents aliasing.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E7F
Reference: 2024-2028 Question Pool · E7 - Practical Circuits
Key Concepts
Verified Content
Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E7F topic.