LOW FREQUENCY UNDERWATER SOUND CALIBRATION SOURCE

MOVING-COIL TRANSDUCERS ARE USUALLY ASSOCIATED WITH LOW POWER, LOW EFFICIENCY, BROADBAND AND VERY LOW FREQUENCY APPLICATIONS. THE RECENT INTRODUCTION OF RARE EARTH PERMANENT MAGNETIC MATERIALS HAVING HIGH ENERGY DENSITIES AND THE RECENT DEVELOPMENT OF BETTER DESIGN TECHNIQUES SIGNIFICANTLY IMPROVE EFFICIENCY, POWER HANDLING ABILITY, AND HIGH FREQUENCY OPERATION. THE APPLICATION OF THESE IMPROVEMENTS AND A NEW TECHNIQUE FOR REDUCING DAMPING, THEREBY RAISING Q, ARE PROPOSED TO SATISFY THE HIGH EFFICIENCY, LOW FREQUENCY REQUIREMENT OF THE SOLICITED TASK.