Modulation Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

Share Print Save

A calculator can remove arithmetic without removing judgment. For modulation, wave and sound calculations are sensitive to the chosen medium and to whether the page is working with amplitudes, powers, or ratios. Use the result as a transparent model of the fields on this page, not as a substitute for knowing what those fields mean.

What this calculator does

Use the Modulation Calculator when you want amplitude modulation index from Message signal amplitude (Aₘ), Carrier signal amplitude (A꜀) without building a broader simulation. Supporting cards, if present, expose useful consequences of the same equation rather than introduce unrelated assumptions.

How to use it

Use measured or specified values for Message signal amplitude (Aₘ), Carrier signal amplitude (A꜀). Let the page handle supported unit conversions, but keep the physical convention consistent across the fields. If you are comparing two scenarios, change only the quantity you intend to test so the effect is easy to interpret.

How the calculation works

For amplitude modulation, the page calculates modulation index m = Aₘ/A꜀ from message amplitude and carrier amplitude. Percent modulation is 100m. It does not calculate sideband power or a complete modulated waveform.

Example

Using the default example on the page (Message signal amplitude (Aₘ) = 1; Carrier signal amplitude (A꜀) = 2), the calculator returns amplitude modulation index of 0.5. Use the default result as a hand-check point, then test one input at a time so an inverted ratio or unit mistake becomes obvious.

How to interpret the result

An AM index of 0.5 means 50% modulation in this amplitude-ratio definition. A value near 1 means 100%; values above 1 indicate over-modulation for conventional envelope AM, where distortion can occur.

Limitations and notes

Real acoustic systems can add reflections, damping, frequency dependence, source directivity, background noise, and nonuniform materials that are not represented by a compact formula. Pay particular attention to Message signal amplitude (Aₘ), Carrier signal amplitude (A꜀). If the real system includes effects that are not represented on the form, the calculated number can be internally correct yet incomplete for design. Use governing standards and test data where consequences matter.