The Research And Realization Of The Transceiver In A Underwater Acoustic Communication System

Diminshing land resources to make people look to the sea. With the continuousdevelopment of science and technology, the technology of underwater communicationalso gradually got the attention of people. Both in the field of national defense military,industrial and civilian areas, that whether the underwater communication is smoothaccurate or not is the prerequisites and reliable protection of the underwater activities.Underwater communication system, however, the most basic is also the most criticalproblem is how to design an efficient and stable transmitter to ensure that the correctsignal transfers, at the same time to design a flexible receiver to ensure normal receptionof signals. So in order to solve this problem, the transmitter which match the underwateracoustic transducer and the receiver which can automatically control the gain are designedand debugged respectively in this paper. And the performance of the underwatercommunication system is tested.First of all, in this paper, the background and the practical significance of the study inthe underwater communication is introduced with the brief explanation. And the structureand characteristics of the underwater acoustic transducer is further analyzed as animportant device of energy conversion.The second, in view of the transmitter which drives the acoustic transducer, asdifferent types of power amplifier has different performance and structural, class D poweramplifier is selected out in this paper to design the transmitter in order to realize thesystem with low consumption, high efficiency, stable and reliable, good linear degree andother technical indicators. So the PWM modulation module, the dead zone control module,the driver module, the power amplifier module and the filter output module are designedrespectively. And then to take all the modules in integration to be the underwater acoustictransmitter which meets the requirements.Once again, because of the different underwater propagation distance, the degree ofsignal attenuation is different also. To stable the signal within a certain amount of dynamicrange and is advantageous for subsequent processing also, in this paper, a acoustic receiver with automatic gain control in80dB dynamic range is designed through hardware circuit.And it can reduce the pressure of the programmable chip memory at the same time.At last, the experiment is done in the actual underwater environment to test thetransmitter and receiver which is designed. The result of the experiment shows that theacoustic transmitter works normally with high efficiency and small heat loss. And theperformance of the receiver is stable, that it can stabilize the signal under80dB dynamicrange at the expected amplitude. As a result, the underwater acoustic communicationsystem with stable and reliable performance achieves the expected index.