modulation degree
The modulation depth (m) is a characteristic value of amplitude modulation( AM), which is usually specified as a percentage. It is the ratio of the amplitude of the modulation signal to the amplitude of the carrier frequency.
If the carrier signal is unmodulated, the modulation depth is "0". If the amplitude of the modulation signal is half that of the carrier frequency, the modulation depth is 0.5 or 50%. If both amplitudes are equal, the carrier signal is fully modulated, the modulation depth is then "1". In this case, overmodulation takes place and the modulated signal is distorted.