一种水下激光声通信声源的设计方法

单个激光声脉冲具有脉宽窄、频带宽的特点,不适于远距离水声通信。为了改善激光声通信声源的频谱特性,提高通信性能,采用对激光声进行调制的方法,建立了调制激光声码元的数学模型,基于该模型,提出一种调制激光声源的设计方法,该方法使调制激光声码元频谱的能量集中体现在调制特征的频率上,降低了信号的频谱宽度,更利于激光声信号在水声信道中远距离传播;推导了在热膨胀机制和光击穿机制下调制激光声码元的调制参量,利用实验获得的热膨胀和光击穿激光声脉冲,仿真了该方法下的调制激光声码元,并分析其频谱特征。结果表明,该声源调制方法是正确和有效的。

A source design method for underwater laser-acoustic communication

A single laser-acoustic pulse is not available in long distance underwater acoustic communication due to its spike pulse and wide frequency spectrum.To improve the spectrum of the leaser acoustic signal,and improve its communication performance,the source was modulated.The mathematical model for modulated laser-acoustic code element was established,a source design method for underwater laser-acoustic communication was presented based on the model.The energy of the code element modulated by the method was concentrated at the frequency that represents the modulation,and the band of the signal was reduced,which made it transmit a further distance in underwater acoustic channel.The modulating parameters of code element induced by laser breakdown and thermoelastic mechanism were calculated.The code element modulated with the method was simulated based on laser signals collected in experiments,whose frequency spectrum proved the validity and the serviceability of the method.