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Why does FM sound better than AM?

(www.johndcook.com)
259 points zdw | 2 comments | 13 Oct 24 22:32 UTC | HN request time: 0.414s | source
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dmitrygr ◴[14 Oct 24 00:20 UTC] No.41832956[source]▶
This is 100% nonsense. Phase noise exists too, not just amplitude noise.

The answer is actually rather simple. AM stations are limited to 10KHz band width. FM gets 200KHz. More bandwidth allows representing a higher fidelity signal…

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1. basementcat ◴[14 Oct 24 00:28 UTC] No.41833000[source]▶
It’s more than that. FM is several times less spectrum efficient than AM and needs more bandwidth to transmit the same information.

https://en.m.wikipedia.org/wiki/Carson_bandwidth_rule

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2. IX-103 ◴[14 Oct 24 01:24 UTC] No.41833302[source]▶
You provided a citation, but it doesn't prove your point. In general frequency modulation is more efficient than amplitude modulation (but requires more complicated receivers). For example GMSK in the 2G standard GSM replaced the less efficient 1G AMPS system which used amplitude modulation.