This tool calculates the **modulation index**, which quantifies how much a carrier wave is modulated by the input signal in either **AM** (Amplitude Modulation) or **FM** (Frequency Modulation).

Amplitude Modulation (AM)

The modulation index \( m \) is given by: \[ m = \frac{A_m}{A_c} \] Where \( A_m \) is the peak amplitude of the modulating signal and \( A_c \) is the carrier amplitude.

• m < 1: Undermodulated
• m = 1: 100% modulation (ideal)
• m > 1: Overmodulated — distortion likely

Frequency Modulation (FM)

The FM modulation index \( \beta \) is: \[ \beta = \frac{\Delta f}{f_m} \] Where:

• \( \Delta f \): Frequency deviation (Hz)
• \( f_m \): Modulating frequency (Hz)

A higher index means more bandwidth. Narrowband FM (β < 1), wideband FM (β > 1).

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