Characteristics of the Transmission System
As sonar signals propagate out of the dolphin’s head, a definite acoustic field is formed that is governed by the size of the animal’s head, the peak frequency of the signals, the area of the sound production mechanism, and the amount of focusing within the melon and at the melon-water interface. The acoustic near field will form in the vicinity of the dolphin’s head as it would near the transmitting surface of any energy radiator. The concept of a near field is often difficult to grasp since many explanations are embroiled in mathematics that seem to confuse rather than clarify the issue. In this section, a simple model will be used to discuss the notion of the near and far acoustic field of a radiator and to provide insights into the physics involved with the propagation of acoustic energy from a dolphin’s head.
KeywordsPeak Frequency Acoustic Field Acoustic Pressure Beam Pattern Circular Aperture
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