CAJ | 학술논문

在水声技术研究中最主要的声学量是水声声压，各种声纳设备的主要电声参数都是通过检测水声声压值来计算。水声声压的校准测试一般都在有限水域的自由场中进行，这就需要克服声场中的反射影响。通常情况下都是用脉冲声信号法来实现直达信号与回波信号的分离，但它在窄带通道内的瞬时处理会造成脉冲信号的扭曲，随着频率的降低，效果也会下降。这就造成了有限水域内自由场校准中频率下限的限制。针对有限水域内的水声声压自由场低频校准问题，介绍了一种能在有限水域内降低校准频率的方法，它利用复数线性扫频信号与信号处理方法相结合，从发射器、水池和接收器体系的目标特性分析开始，开展对自由场发射器与接收器间传输阻抗的估计，能有效地降低有限水域内校准的频率下限，满足声纳设备对低频性能的校准需求。本文通过对该方法原理的理论分析和实验验证研究，并与自由场脉冲声法测量结果的比较，获得了相当吻合的结果。
재수성기술연구중최주요적성학량시수성성압，각충성납설비적주요전성삼수도시통과검측수성성압치래계산。수성성압적교준측시일반도재유한수역적자유장중진행，저취수요극복성장중적반사영향。통상정황하도시용맥충성신호법래실현직체신호여회파신호적분리，단타재착대통도내적순시처리회조성맥충신호적뉴곡，수착빈솔적강저，효과야회하강。저취조성료유한수역내자유장교준중빈솔하한적한제。침대유한수역내적수성성압자유장저빈교준문제，개소료일충능재유한수역내강저교준빈솔적방법，타이용복수선성소빈신호여신호처리방법상결합，종발사기、수지화접수기체계적목표특성분석개시，개전대자유장발사기여접수기간전수조항적고계，능유효지강저유한수역내교준적빈솔하한，만족성납설비대저빈성능적교준수구。본문통과대해방법원리적이론분석화실험험증연구，병여자유장맥충성법측량결과적비교，획득료상당문합적결과。
Underwater acoustic pressure is the most important acoustic quantity in the research of underwater acoustics.The main electric and acoustics parameters are all calculated by sound pressure.The calibration of underwater sound pressure is usually carried out in the free field with a limited water region,in which the reflection from boundaries must be eliminated.In standard facilities,tone burst signal radiation and receiving technique is usually used.A direct signal from a proj ector and echo signals are divided by time selection method.In order to suppress random noise,narrow band filtration is used.Time selection method disadvantages are as following:pulse signal form distortion by transient processes in narrow band path,time selection efficiency decrease along with frequency decrease(as consequence-limitation of free field calibration lower frequency),long time of hydrophone detailed frequency response measurement,need in coherent accumulation for signal-to-noise ration increase.To solve these problems,the paper present a method to reduce the calibration frequency within limited water region.With the combination of complex linear chirp signals and signal processing method,the target character of the system that is compromised of proj ectors,water tank and receiver was estimated.The reflective effects were eliminated and the free field was obtained which reduced the low frequency restriction of calibration and satisfied the requirements of sonar calibration in the lower frequency range.The theory of the measurement method and experiments were studied,and good agreements were shown between the results of using this method and free field pulse method.