Modulation Depth (AM)
For AM, the modulation depth is expressed as a percentage and represents the extent of the amplitude variation. At 0% depth, the output amplitude is half of the selected value. At 100% depth, the output amplitude equals the selected value. For most function generators, you can set the modulation depth between 0% and 120%. The default is 100%.
If you select the External modulating source (see Modulating Source), the carrier waveform is modulated with an external waveform. The modulation depth is controlled by the signal level present on the function generator's external modulation connector.