| 摘要 |
PURPOSE:To enable the projection of a distinct searching video with an ultrasonic transmitter and receiver mounted in the bottom of a ship, by making the sensitivity for forming a beam pattern low with respect to the noise direction if there is the noise from a specific direction. CONSTITUTION:The beam angle set signal of a beam angle set section BA which sends the beam angle set signal as an address signal to the address terminals A0-A4 of a memory ROM is sent to a generation section BP for a beam direction set pulse as well. The section BP is inputted with said beam angle set signal, that is, the signal indicating whether the beam direction is from upper or lower side or the angle that the beam possesses. The section BP upon receiving such input applies the beam direction set pulse to mixing circuits MI1- MX15. The signal for determining the kind of the beam as an address signal for determining the kind of the beam is then inputted from a determination section BK for the kind of the beam to the address terminals A5-A7 of the memory ROM. |
