What is modulation factor?

1. Modulation factor is defined as the ratio of the change in the amplitude of the carrier wave to the amplitude of the original carrier wave.
2. The modulation factor can be obtained by dividing frequency deviation by the modulation frequency.
3. A modulation factor can also be called a modulation index.
4. The degree of modulation shouldn't ever go above $100\%$ for effective modulation.
5. The modulation factor of effective modulation is 1
6. The value of the modulation index must be between 0 to 1.
7. If the value of the modulation index is greater than 1, then it results in severe distortion.