Updated: Dec 9, 2025 | Source: 2023-2027 Question Pool | Topic: G7C
G7C04G7C

How is a product detector used?

Deep Dive: G7C04

The correct answer is D: Used in a single sideband receiver to extract the modulated signal. How a product detector is used is in a single sideband receiver to extract the modulated signal. Product detectors mix the SSB signal with a local oscillator to recover the audio. For amateur radio operators, this is how SSB receivers work. Understanding this helps when designing SSB receivers.

Why Other Answers Are Wrong

Option A: Incorrect. Product detectors aren't used in test gear to detect spurious mixing products - that's done by spectrum analyzers, not product detectors. Spurious detection isn't the use. Option B: Incorrect. Product detectors aren't used in transmitters for frequency multiplication - that's done by multipliers, not product detectors. Frequency multiplication isn't the use. Option C: Incorrect. Product detectors aren't used in FM receivers to filter sidebands - FM receivers use discriminators, not product detectors. FM demodulation is different.

Exam Tip

Product detector use = in SSB receiver to extract modulated signal. Think 'P'roduct 'D'etector = 'P'roduces 'D'emodulated audio in 'S'SB receiver. Product detectors mix SSB signal with local oscillator to recover audio. Not spurious detection, not frequency multiplication, not FM filtering - just SSB demodulation.

Memory Aid

Product detector use = in SSB receiver to extract modulated signal. Think 'P'roduct 'D'etector = 'P'roduces 'D'emodulated audio. Product detectors mix SSB signal with local oscillator to recover audio. Essential for SSB reception.

Real-World Example

An SSB receiver: The product detector mixes the incoming SSB signal with a local oscillator (BFO - Beat Frequency Oscillator). This mixing process extracts the audio from the SSB signal. Product detectors are essential for SSB reception - they're how SSB receivers recover the audio. This is the primary use of product detectors.

Source & Coverage

Question Pool: 2023-2027 Question Pool

Subelement: G7C

Reference: 2023-2027 Question Pool · G7 - Practical Circuits

Key Concepts

Product detector SSB receiver Extract modulated signal Demodulation

Verified Content

Question from the official FCC General Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the G7C topic.