Acoustic signals are sounds that carry information through vibrations in a medium, such as air or water. These signals can be produced by various sources, including animals, machines, and natural phenomena. For example, whales use acoustic signals to communicate over long distances in the ocean, while birds use songs to attract mates or defend territories. In technology, acoustic signals are utilized in devices like microphones and speakers to convert sound waves into electrical signals and vice versa. Additionally, ultrasound technology employs high-frequency acoustic signals for medical imaging, allowing doctors to visualize internal organs without invasive procedures.