Superheterodyne Receiver Blocks: Match Each Stage to Its Role List I (Stage) A. RF amplifier B. Loudspeaker C. Demodulator D. IF amplifier List II (Function) Amplifies received carrier along with its sidebands (preselects front-end) Provides acoustic (audio) output Accepts IF input and delivers AF (baseband) output by detection Fixed-tuned amplification at the intermediate frequency

Introduction / Context:
Superheterodyne receivers divide processing into RF front-end filtering/amplification, frequency conversion to a fixed IF, selective amplification, and baseband detection, finally driving an audio transducer. Knowing each block's role is foundational for radio design and troubleshooting.

Given Data / Assumptions:

• RF amplifier precedes the mixer, improving sensitivity and selectivity.
• IF amplifier operates at a fixed intermediate frequency with narrowband selectivity.
• Demodulator recovers the audio/baseband (AF) from IF.
• Loudspeaker converts electrical AF to sound.

Concept / Approach:

Assign each stage to the description that best matches its standard function within a superhet architecture.

Step-by-Step Solution:

Verification / Alternative check:

Standard block diagrams of AM/FM superhet receivers confirm: antenna → RF amp → mixer/LO → IF filter/amp → detector → AF amp → loudspeaker.

Why Other Options Are Wrong:

Swapped mappings would misplace functions (e.g., a loudspeaker cannot amplify IF, and an IF amplifier does not produce audio). RF amplification must precede conversion to preserve signal quality.

Common Pitfalls:

Confusing RF and IF roles, or assuming the demodulator operates directly at RF; while direct-conversion radios exist, this question clearly targets superheterodyne architecture.

Final Answer:

A-1, B-2, C-3, D-4