| 摘要 |
PURPOSE:To facilitate the specifying of the bearing directivity of a video while preventing the decline in the detection capacity by changing the bearing of a transmission beam continuously while varying the phase of a transmission signal to turn a spiral directivity beam continuously in the azimuth direction. CONSTITUTION:A digital data 61 from a memory reading (ROM)51 is converted into an analog signal 62 with a D/A converter 52 while turned to a sine wave with a low-pass filter 53 and transmitted as sound wave with a transmitter/receiver 7 via a transmitter 9 and a switch 8. Data 61 read out of each ROM corresponding to the sine wave level has a design value written thereinto beforehand to cause a continuous change of a spiral directivity beam or to cause a continuous change in the electric phase value. Then, when forming a beam B-m, a transmission signal is fed to transmitter/receiver elements from E1-El and subsequently, the elements E2-El+1 are switched over to form a beam B-m+1. Thus, the detection capacity of a sonar can be upgraded. |
