Unmodulated

Contact calls are soft, unmodulated sounds made by individuals that have been separated from their group and may be responded to with a "contact answer" call that starts out loud, but becomes softer.

It is thus defined as: : where and are the modulation amplitude and carrier amplitude, respectively; the modulation amplitude is the peak (positive or negative) change in the RF amplitude from its unmodulated value.

Modulation index As in other modulation systems,the modulation index indicates by how much the modulated variable varies around its unmodulated level.

Modulation index The AM modulation index is a measure based on the ratio of the modulation excursions of the RF signal to the level of the unmodulated carrier.

The unmodulated radio frequency carrier is applied to the control grids of both tubes.