The Research And Implementation Of A Direct-drive Emitter System For Underwater Acoustic Communication

The system of acoustic emitter, an important part in the underwater communication system can change the electronic signal to acoustic signal. To provide good communication research environment, the emitter must be well linear to emit the FSK, Time-Delay Coding signals witch suit the underwater channel. The normal acoustic emitter system used recently has a structure with MOSFET and power transformer. But the transformer is too heavy to apply in laboratory environment and near underwater communication. So, the design of direct drive acoustic emitter system is needed. The direct drive acoustic emitter is composing with Parts of semiconductor. To drive transducer, which has high impedance, the emitter must output high voltage with high current. To design such an emitter, the circuit must have several stages. The design of emitter is base on the character of transducer, especially the impedance of transducer. Before the design of emitter, the character of transducer which can be described by the character of mechanical syntony must be understood. So do the transistor with high collector-emitter voltage and high collector current. Because of the stages of circuit, it stability can be worse, so the measure of compensation must be designed in the circuit. And still the protection circuit is very important in such a circuit with high voltage and high power. According to the test it is prove that such a direct drive acoustic emitter can convert the signal with low voltage and power to the signal with high voltage and power to drive the transducer directly. So such emitter can be applied in the research system and communication system without long distance.