Common blocks in AM and FM receivers: Which of the following circuit blocks are the same in both AM and FM superheterodyne receivers?

Introduction / Context:
AM and FM receivers share a similar overall architecture, particularly in the superheterodyne design, though the demodulator differs in implementation.

Given Data / Assumptions:

• Both receivers use frequency conversion to a common IF stage.
• Standard blocks: RF tuning, mixer, IF amplification, demodulation, AGC.

Concept / Approach:

The IF stage provides selectivity and gain, common to both AM and FM receivers. AGC is also employed in both to regulate gain and improve reception quality. Demodulators exist in both, although their design differs (envelope detector for AM, discriminator for FM).

Step-by-Step Solution:

Verification / Alternative check:

Superheterodyne block diagrams of both AM and FM receivers confirm the same structural blocks, though tuned differently.

Why Other Options Are Wrong:

• Individual choices are correct but incomplete.
• “None of the above” contradicts practical designs.

Common Pitfalls:

• Thinking that FM receivers do not use AGC (they do, though implementation differs).

Final Answer:

All of the above.