Deep Dive: E7C09
The correct answer is D: A filter for low-level signals made using quartz crystals. What is a crystal lattice filter is a filter for low-level signals made using quartz crystals. Crystal lattice filters use quartz crystals for filtering. For amateur radio operators, this is important for filter design. Understanding this helps when working with crystal filters.
Why Other Answers Are Wrong
Option A: Incorrect. Power supply filter made with interlaced quartz crystals isn't crystal lattice - crystal lattice is for low-level signals. Power supply filter isn't crystal lattice. Option B: Incorrect. Audio filter made with four crystals at 1 kHz intervals isn't crystal lattice - crystal lattice is for low-level signals using crystals. Audio filter isn't crystal lattice. Option C: Incorrect. Filter using lattice-shaped crystals for high-Q isn't specific enough - crystal lattice is for low-level signals using crystals. Lattice-shaped isn't specific.
Exam Tip
Crystal lattice filter = filter for low-level signals made using quartz crystals. Think 'C'rystal 'L'attice = 'C'rystal 'L'ow-level filter. Crystal lattice filters use quartz crystals for filtering. Not power supply, not audio, not just lattice-shaped - just filter for low-level signals using crystals.
Memory Aid
Crystal lattice filter = filter for low-level signals made using quartz crystals. Think 'C'rystal 'L'attice = 'L'ow-level 'C'rystal filter. Crystal lattice filters use quartz crystals for filtering. Important for filter design.
Real-World Example
A crystal lattice filter: It's a filter for low-level signals made using quartz crystals. Multiple crystals are arranged in a lattice configuration to create the filter. This is what it is - filter for low-level signals using crystals.
Source & Coverage
Question Pool: 2024-2028 Question Pool
Subelement: E7C
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 E7C topic.