Which of the following is most frequently used as a band-pass or notch filter in VHF and UHF transceivers?
The correct answer is B: A helical filter. Which of the following is most frequently used as a band-pass or notch filter in VHF and UHF transceivers is a helical filter. Helical filters are commonly used in VHF/UHF transceivers. For amateur radio operators, this is important for filter design. Understanding this helps when working with transceivers.
Exam Tip
Band-pass/notch filter in VHF/UHF transceivers = helical filter. Think 'H'elical 'F'ilter = 'H'igh frequency (VHF/UHF). Helical filters are commonly used in VHF/UHF transceivers. Not Sallen-Key, not swinging choke, not FIR - just helical filter.
Memory Aid
"Band-pass/notch filter in VHF/UHF transceivers = helical filter. Think 'H'elical = 'V'HF/'U'HF. Helical filters are commonly used in VHF/UHF transceivers. Important for filter design."
Real-World Application
Band-pass or notch filters in VHF and UHF transceivers: A helical filter is most frequently used. Helical filters provide good performance at VHF/UHF frequencies. This is the filter - helical filter for VHF/UHF transceivers.
Key Concepts
Why Other Options Are Wrong
Option A (Sallen-Key filter): Incorrect. Sallen-Key isn't most frequently used - helical filter is used in VHF/UHF transceivers. Sallen-Key isn't the answer.
Option C (Swinging choke filter): Incorrect. Swinging choke isn't most frequently used - helical filter is used in VHF/UHF transceivers. Swinging choke isn't the answer.
Option D (Finite impulse response filter): Incorrect. FIR filter isn't most frequently used - helical filter is used in VHF/UHF transceivers. FIR filter isn't the answer.
题目解析
The correct answer is B: A helical filter. Which of the following is most frequently used as a band-pass or notch filter in VHF and UHF transceivers is a helical filter. Helical filters are commonly used in VHF/UHF transceivers. For amateur radio operators, this is important for filter design. Understanding this helps when working with transceivers.
考试技巧
Band-pass/notch filter in VHF/UHF transceivers = helical filter. Think 'H'elical 'F'ilter = 'H'igh frequency (VHF/UHF). Helical filters are commonly used in VHF/UHF transceivers. Not Sallen-Key, not swinging choke, not FIR - just helical filter.
记忆口诀
Band-pass/notch filter in VHF/UHF transceivers = helical filter. Think 'H'elical = 'V'HF/'U'HF. Helical filters are commonly used in VHF/UHF transceivers. Important for filter design.
实际应用示例
Band-pass or notch filters in VHF and UHF transceivers: A helical filter is most frequently used. Helical filters provide good performance at VHF/UHF frequencies. This is the filter - helical filter for VHF/UHF transceivers.
错误选项分析
Option A (Sallen-Key filter): Incorrect. Sallen-Key isn't most frequently used - helical filter is used in VHF/UHF transceivers. Sallen-Key isn't the answer. Option C (Swinging choke filter): Incorrect. Swinging choke isn't most frequently used - helical filter is used in VHF/UHF transceivers. Swinging choke isn't the answer. Option D (Finite impulse response filter): Incorrect. FIR filter isn't most frequently used - helical filter is used in VHF/UHF transceivers. FIR filter isn't the answer.
知识点
Most frequently used, Band-pass or notch filter, VHF and UHF transceivers, Helical filter
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.