Amateur Extra › E7 Practical Circuits › E7E06
E7E06
Why is de-emphasis used in FM communications receivers?
Pick an answer to check it.
Answer: A. For compatibility with transmitters using phase modulation
Phase modulation naturally boosts higher audio frequencies, much like pre-emphasis. De-emphasis in the receiver cuts them back down, keeping the receiver compatible with PM transmitters.
Tip: PM boosts highs; de-emphasis restores balance.