A sound projector for acoustic tomography and global ocean monitoring
A sound projector for acoustic tomography and global ocean monitoring
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DOI：
10.1109/joe.2003.811888
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发表时间：
2003-04-01
影响因子：
4.1
通讯作者：
Webb, DC
中科院分区：
文献类型：
--
作者：
Morozov, AK;Webb, DC
远程水声系统，如用于海洋声层析成像的系统，需要覆盖较宽频带的低频信号。为了满足这一需求，开发了一种基于可调谐窄带高效声音放映机的新型设计。投影仪通过机械调谐谐振器管(或管风琴管)来传输扫频信号，以匹配参考信号的频率和相位。谐振器管投影仪由放置在两个同轴安装的管之间的对称压力平衡Tonpiz驱动器组成。通皮尔茨声学驱动器由两个活塞组成，两个活塞由预加载的陶瓷堆隔开。谐振管是一种简单的。高效、窄带、中等输出的投影仪，可在任何海洋深度运行。两个投影管都有槽(或通风口)，这些槽(或通风口)逐渐被滑动的同轴管状套筒覆盖或露出。频率随袖子位置的不同而不同。计算机控制的机电致动器沿着管子移动圆柱形套筒，使投影仪保持在扫频信号的瞬时频率上的共振。在135-S传输期间，执行器平稳地在200至300赫兹的带宽内调谐谐振器管的频率。计算机合成线性调频信号；比较发射信号和参考信号之间的相位；并使用锁相环(PLL)系统，保持谐振器管的频率与驱动器的频率共振。估计的锁相环精度优于3度相位误差。通过有限元分析和电气等效电路仿真对系统进行了分析。投影仪样机首先在马萨诸塞州伍兹霍尔的伍兹霍尔海洋研究所(WHOI)码头进行测试，后来在2001年11月RN南点的一次航行中在太平洋进行测试。
Long-range underwater acoustic systems, such as those used in ocean acoustic tomography, require low-frequency signals covering a broad frequency band. To meet this requirement, a novel design based on of a tunable narrow-band high-efficiency sound projector has been exploited. The projector transmits a frequency sweep signal by mechanically tuning a resonator tube (or organ pipe) to match the frequency and phase of a reference signal. The resonator tube projector consists of a symmetrical pressure-balanced Tonpilz driver placed between two coaxially mounted tubes. The Tonpilz acoustical driver is composed of two pistons separated by preloaded ceramic stacks. The resonant tube is a simple. efficient, narrow-band, medium-output projector that operates at any ocean depth. Both projector tubes have slots (or vents), which are progressively covered or uncovered by sliding coaxial tubular sleeves. The frequency varies with the sleeves position. A computer-controlled electromechanical actuator moves the cylindrical sleeves along the tubes, keeping the projector in resonance at the instantaneous frequency of a swept frequency signal. The actuator smoothly tunes the frequency of the resonator tube in the bandwidth of 200 to 300 Hz during a 135-s transmission. A computer synthesizes the linear frequency-modulated signal; compares the phase between transmitted and reference signals; and, using a phase-lock loop (PLL) system, keeps the resonator tube frequency in resonance with the driver, frequency. The estimated PLL precision is better than 3degrees phase error. The system was analyzed by means of finite element analysis and electrical equivalent circuit simulation. The projector prototype was first tested at the Woods Hole Oceanographic Institution (WHOI) dock in Woods Hole, MA and later in the Pacific Ocean during a voyage of the RN "Point Sur," November 2001.