He experimented with the optimum characteristics of the emitted sound pulse, the frequency profile from beginning to end, to give the best detection performance.

These elements, called projectors, are devices that produce the active sound pulse, or ping.

Arrival time of a sound pulse and phase differences of continuous sound are used for localization of sound sources.

The system emits a sound pulse, that reflects off objects and then back to the system.

As the sound pulse travels through water it encounters objects that are of different density than the surrounding medium, such as fish, that reflect sound back toward the sound source.