Contrast the fundamental difference between a digital signal and an analogue signal.

State one advantage of transmitting information using digital signals rather than analogue signals.

A marine research facility uses underwater acoustic transmitters to mimic animal vocalizations. To cover the entire frequency range of marine mammals, the facility uses a dual-transmitter system consisting of a small-diameter high-frequency transducer and a large-diameter low-frequency transducer.

Explain, using principles of wave diffraction, why transducers of different diameters are necessary to ensure that underwater sound waves of all frequencies spread out uniformly into the surrounding sea.