Basic Qualification · B-003 Station assembly, practice and safety · B-003-005-005
In an SSB/CW receiver, what is the purpose of the intermediate frequency (IF) filter?
- A Suppress spurious signals from the IF amplifier
- B Reject RF from the product detector, passing only audio
- C Provide most of the selectivity of the receiver
- D For SSB reception, select the desired sideband
Correct answer: C — Provide most of the selectivity of the receiver. From the official ISED question bank, verified word for word.
Why
The intermediate frequency filter shapes the signal path to block unwanted stations close in frequency, which is exactly what selectivity means. The full explanation — and one for every question — is in Pro.
Practise this section
Building a station safely: power supplies, grounding, RF exposure, lightning, feedline routing, and what a transmitter, receiver and transceiver actually do.