Advanced Qualification · A-006 Receivers · A-006-002-008
In a superheterodyne receiver without an RF amplifier, the input to the mixer stage has a variable capacitor in parallel with an inductance. The variable capacitor is for:
- A tuning the receiver preselector to the reception frequency
- B tuning both the antenna and the beat-frequency oscillator
- C tuning the beat-frequency oscillator
- D tuning both the antenna and the local oscillator
Correct answer: A — tuning the receiver preselector to the reception frequency. From the official ISED question bank, verified word for word.
Why
In a superheterodyne receiver lacking an RF amplifier, that variable capacitor and inductor form a tuned circuit right at the mixer input. The full explanation — and one for every question — is in Pro.
Practise this section
Receivers: superheterodyne design, selectivity, sensitivity, images, AGC and noise.