What is the typical modulation depth for AM broadcasting?

The typical modulation depth for AM broadcasting is generally around 100%. This means the amplitude of the carrier signal varies between the maximum and minimum levels, effectively utilizing the full range of modulation to convey the audio signal. When modulation depth is at 100%, the amplitude of the modulated signal oscillates fully from 0% (silence) to the peak carrier amplitude, allowing for the most effective transmission of the audio information.

A modulation depth of 100% ensures that the signal is strong and can be received more reliably, maximizing the signal-to-noise ratio and minimizing distortion. Operating at 100% allows for the best use of the transmitter's power, and while the carrier can theoretically go beyond this point—resulting in overmodulation—doing so can lead to distortion and interference with adjacent channels.

A modulation depth of 50% or 75% would provide a less robust signal, as these levels do not utilize the full capacity of the system. On the other hand, 125% modulation depth is not ideal for broadcasting, as it suggests overmodulation that can cause distortion, splatter, and other issues that compromise the quality of the transmitted audio and can interfere with other broadcasts. Therefore, 100% modulation is the standard