AM / FM Modulation

How does a song travel through the air? By hitching a ride on a radio carrier. Watch a message modulate the amplitude or frequency of a carrier wave.

AM / FM ModulationLive

how radio carries sound

Controls

Presets

Modulation

Carrier frequency

Message frequency

Modulation index

Radio hides a low-frequency message inside a high-frequency carrier. AM varies the carrier's amplitude with the message; FM varies its frequency. FM resists noise better, which is why music stations use it. Educational tool.

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Data Inspector

ModeAmplitude (AM)

Carrier / message20 / 2

Modulation index0.70

Modulation depth70%

Governing equation

s (t) = (1 + 0.70 cos (2 π \cdot 2 t)) cos (2 π \cdot 20 t)

Reading this result: AM varies the carrier's amplitude with the 2 Hz message at 70% depth. The envelope stays positive, so a simple envelope detector recovers the message cleanly. The 20 Hz carrier is far above the message so the two separate at the receiver.

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How it works

Modulation encodes a low-frequency message onto a high-frequency carrier. AM varies the carrier's amplitude in step with the message; FM varies its instantaneous frequency. FM shrugs off amplitude noise, which is why it delivers cleaner audio than AM. Educational tool.

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Frequently asked questions

Is this am fm modulation simulator tool really free?▾

Yes. AM / FM Modulation runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.

Do I need to install anything?▾

No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.

Can I save or share my simulation?▾

Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.

How accurate are the results?▾

The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.