Advanced Qualification · A-006 Receivers · A-006-004-011
What circuit combines signals from an IF amplifier stage and a beat-frequency oscillator (BFO), to produce an audio signal?
- A A product detector circuit
- B An AGC circuit
- C A power supply circuit
- D A VFO circuit
Correct answer: A — A product detector circuit. From the official ISED question bank, verified word for word.
Why
A product detector circuit is the correct choice because it is the specific stage in a receiver that mixes the intermediate frequency signal with the beat-frequency oscillator output to create the audible sound you hear. The full explanation — and one for every question — is in Pro.
Practise this section
Receivers: superheterodyne design, selectivity, sensitivity, images, AGC and noise.