Advanced Qualification · A-006 Receivers · A-006-002-002
A superheterodyne receiver designed for SSB reception must have a beat-frequency oscillator (BFO) because:
- A it reduces the pass-band of the IF stages
- B it beats with the receiver carrier to produce the missing sideband
- C the suppressed carrier must be replaced for detection
- D it phases out the unwanted sideband signal
Correct answer: C — the suppressed carrier must be replaced for detection. From the official ISED question bank, verified word for word.
Why
In single-sideband (SSB) transmission, the carrier signal is intentionally removed to save power, but a receiver needs that carrier reference to reconstruct the original voice audio. The full explanation — and one for every question — is in Pro.
Practise this section
Receivers: superheterodyne design, selectivity, sensitivity, images, AGC and noise.