| 摘要 |
PURPOSE:To make it possible to transmit receiving SONAR in such a state that the selective property of transmission and sufficient irradiation energy at a remote place are secured, by making the wave fronts of transmission bifocal and setting the distance between focuses of the wave fronts to an appropriate medium distance. CONSTITUTION:The delay map of a delay circuit forming a transmission beam former is preset so that beams transmitted from and received by a probe 3 form wave fronts 31a, 31b. That is, it is formed so that the wave front 31a is formed by the upper half of the delay circuit, that is, the left half of an array and the wave front 31a is formed by the lower half of said delay circuit, that is, the right half of the array. These two wave fronts are respectively condensed to points L, R and, even when the distance DELTAA between points L, R is properly small, sufficient sound pressure can be obtained at the intermediate point M therebetween. |
