The Dolphin Sonar System

The Larynx-Melon-Vestibular.-Lips (LMVL) Mtodel of the dolphin sonar is presented, based on the following system components: ECHOLOCATION PULSE ("clicks") The larynx, operating as a saw-tooth oscillator, is the source of echoloration pulses. o The output pulses (clicks) couple into the melon through impedance-matching nasal ducts. o The melon, acting as a slow-waveguide, forms narrow end-fire beam pattern TONAL PHONATION (whistles") Vestibular lips between the premaxillary sac and the vestibular sac are the source of the tonal phonation (so-called "whistles") o Lip-modulations result from lip-pressure and pressure variations in the premaxillary sac actuated by the nasal-plug muscles. o Lip-modulated tonal phonations are coupled to the water by means of a Sims' "bubble transducer", represented by the vestibular sac. This model, though not "politically correct", can account for most (if not all) of the experimentally observed characteristics of the dolphin sonar. Physical models of the Larynx-Melon-Vestibular-Lips (LMVL) system components, designed in Phase-I and fabricated and tested in PhaseII, should result in validation of the LMVL Model of the dolphin sonar system. Anticipated Benefits/Potential Applications - Clarification of the mechanism and sites of the dolphin sonar phonations and a validated model of the dolphin sonar system.