Advanced Qualification · A-006 Receivers · A-006-002-001
The mixer stage of a superheterodyne receiver is used to:
- A allow a number of IF frequencies to be used
- B remove image signals from the receiver
- C produce an audio frequency for the speaker
- D change the frequency of the incoming signal to that of the IF
Correct answer: D — change the frequency of the incoming signal to that of the IF. From the official ISED question bank, verified word for word.
Why
The mixer stage takes the radio signal you tuned in and shifts its frequency down to a fixed intermediate frequency, or IF, so the rest of the receiver can process it consistently regardless of the station you are listening to. The full explanation — and one for every question — is in Pro.
Practise this section
Receivers: superheterodyne design, selectivity, sensitivity, images, AGC and noise.