Deep Dive: G7C01
The correct answer is B: Filter. The circuit used to select one of the sidebands from a balanced modulator is a filter. Balanced modulators produce double-sideband output; a filter selects either the upper or lower sideband. For amateur radio operators, this is how SSB is generated. Understanding this helps when designing SSB transmitters.
Why Other Answers Are Wrong
Option A (Carrier oscillator): Incorrect. Carrier oscillator generates the carrier, it doesn't select sidebands. Carrier oscillator is for modulation, not sideband selection. Option C (IF amplifier): Incorrect. IF amplifier amplifies intermediate frequency, it doesn't select sidebands. IF amplifier is for amplification, not sideband selection. Option D (RF amplifier): Incorrect. RF amplifier amplifies RF signals, it doesn't select sidebands. RF amplifier is for amplification, not sideband selection.
Exam Tip
Select sideband from balanced modulator = filter. Think 'S'elect 'S'ideband = 'S'elective 'F'ilter. Balanced modulators produce double-sideband; filter selects upper or lower sideband. Not carrier oscillator, not IF/RF amplifier - just filter.
Memory Aid
Select sideband from balanced modulator = filter. Think 'S'elect 'S'ideband = 'S'elective 'F'ilter. Balanced modulators produce double-sideband; filter selects upper or lower sideband. Essential for SSB generation.
Real-World Example
A balanced modulator produces double-sideband output (USB and LSB). A filter (crystal or mechanical) selects either the upper sideband or lower sideband, rejecting the other. This is how SSB is generated - balanced modulator plus filter. The filter is essential for sideband selection.
Source & Coverage
Question Pool: 2023-2027 Question Pool
Subelement: G7C
Reference: 2023-2027 Question Pool · G7 - Practical Circuits
Key Concepts
Verified Content
Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G7C topic.