Advanced Qualification · A-006 Receivers · A-006-002-007
In a superheterodyne receiver, a stage before the IF amplifier has a variable capacitor in parallel with a trimmer capacitor and an inductance. The variable capacitor is for:
- Atuning of the local oscillator (LO)
- Btuning both the antenna and the BFO
- Ctuning of the beat-frequency oscillator (BFO)
- Dtuning both the antenna and the LO
Correct answer: A — tuning of the local oscillator (LO). From the official ISED question bank, verified word for word.
Why
In a superheterodyne receiver, the local oscillator generates a signal that mixes with the incoming radio wave to create a fixed intermediate frequency. The full explanation — and one for every question — is in Pro.
Practise this section
Receivers is section A-006 of the Advanced exam: Receivers: superheterodyne design, selectivity, sensitivity, images, AGC and noise.
Drill A-006 — free, no account