The possibility of using nonlinear effects in hydroacoustic systems with parametric radiation mode for profiling the bottom and bottom sediments attracts the attention of both domestic and foreign specialists. The use of parametric antennas in hydroacoustic equipment allows, due to their high directivity and low side field level, to increase the information content and accuracy in detecting and determining the coordinates of underwater objects, and to obtain additional features for recognition. The efficiency of using a parametric profiler for solving problems that require high resolution is justified. A block diagram of a parametric profiler for studying the layered structure is developed. The features of the signal generator and the amplification unit are considered. The characteristics of the radiating antenna were measured under laboratory conditions. It is shown that the directivity characteristic is constant in the operating frequency range and the acoustic power at the output makes it possible to solve the tasks of sounding up to 10 m into the ground. A record of the soil profile was obtained, confirming the operability of the system. In the future, the results will be used in full-scale conditions with the use of cepstral echo processing.
Keywords: profilograph, parametric antenna, kepstr, block diagram, signal generator, power amplifier, directional pattern, amplitude-frequency response, pump antenna, ground profile
The use of a separate receiving antenna at different frequencies in parametric acoustic systems is associated with the irreversibility of nonlinear processes underlying its principle of operation. The paper considers the results of experimental and theoretical studies to assess the influence of external elements on the amplitude-frequency response of a piezoceramic acoustic antenna. The structural scheme of the experimental setup is considered. It is shown that parallel connection of an external inductance to a piezoelectric element allows shifting the antiresonance frequency of an acoustic antenna, which leads to an increase in both the signal amplitude at the antenna output and an increase in the complex resistance module at the operating frequency.
Keywords: acoustic antenna, the sensitivity of the receiving antenna, the amplitude-frequency characteristic, the modulus of the complex resistance
Within the framework of solving the problem of increasing the effectiveness of the directional properties of adaptive systems with parametric sonar emitting antenna in the results of generalization of theoretical and experimental studies of the effect of hydro-irregularities on the characteristic parameter of the antenna. A comparison of the results of calculations of the antenna directivity characteristic parameter derived from the model Khokhlova-Zabolotskaya-Kuznetsova, with the results of experimental measurements of the directional properties of the parametric array. We obtain the normalized dependence of the width of the parametric characteristics of the antenna by lowering the difference frequency from the center frequency of the pump waves of 5 to 16 times. The influence of changes in the speed of sound in the direction of the parametric array. We obtain the normalized dependence of the width of the antenna characteristics of the parametric values of the sound velocity at the surface of the pump transducer. It was found that the greatest impact on the characteristic parameter of the antenna has a change in the speed of sound to a distance equal to the lengths of 1-2 zone diffraction of the pump waves.
Keywords: adaptive sonar system, efficiency, parametric antenna, directivity characteristic
The paper presents the results of theoretical studies of the problem assess the impact of structural features in the design phase in the direction of the acoustic antennas. Consider the generalized algorithm of forming directional characteristics of a special form in the application hydroacoustic problems and solutions of the generalized problem of optimizing the characteristics of antennas and modular design principle. Optimization problem proposed to divide into separate components: optimization of antenna characteristics and optimization of tactical performance speaker system that comprehensively affect the choice of antenna design. The method of constructing an antenna with a pie chart in the horizontal plane when the parametric antenna sector review contains some highly directional converters pumping flat aperture.
Keywords: acoustic antenna, directivity characteristic, sector
Application for monitoring ice conditions devices based on nonlinear acoustics using parametric radiating antenna takes into consideration such characteristics of the formation of the acoustic field, as having both low-frequency difference frequency formed as a result of the nonlinear interaction of two close by the value of the pump waves, and, in fact, high-frequency radiation source pump waves Development of instruments for acoustic monitoring ice conditions require consideration of all possible real oceanographic situations in which they will operate. The article discusses the results of the development of a system for monitoring the panorama of ice conditions in the parametric mode sonar. The analysis of the formation and propagation of the probing signals into acoustic channel parametric meter ice thickness is formulated the principle of measuring the thickness of the reflection (scattering) of the acoustic signals from a locally stratified system with blurred boundaries. Mathematical modeling of the acoustic channel power meter ice thickness and "windows of transparency" on the basis of the calculation of the critical angles of incidence and refraction. The conclusion of the feasibility of using as reference signals of shear waves.
Keywords: ice monitoring acoustic antenna, the critical angle , the transparency window
To study complex sonar systems, the method of decomposition was suggested. The peculiarities of the method applied to the sonar systems were considered. A four-level hierarchy of decomposition subsystems is proposed. A scheme of the first level of semantic decomposition was presented. Controlled modules allowed to build adaptive systems were described.
Keywords: decomposition, hydro speaker systems, hierarchy of subsystems