Advanced Qualification · A-006 Receivers · A-006-003-003
How much gain should be used in the RF amplifier stage of a receiver?
- A As much gain as possible, short of self-oscillation
- B It depends on the amplification factor the first IF stage
- C Sufficient gain to keep weak signals below the noise of the first mixer stage
- D Sufficient gain to allow weak signals to overcome noise generated in the first mixer stage
Correct answer: D — Sufficient gain to allow weak signals to overcome noise generated in the first mixer stage. From the official ISED question bank, verified word for word.
Why
You need just enough amplification in the radio frequency stage so that faint incoming signals are strong enough to beat the static noise created by the very next part of the receiver, called the first mixer. The full explanation — and one for every question — is in Pro.
Practise this section
Receivers: superheterodyne design, selectivity, sensitivity, images, AGC and noise.