| 摘要 |
<p>The invention concerns transmitting antennas for Doppler logs and current meters. According to the invention, the antenna transducers (701) are distributed on a circular plane base. The polarities, phases and supply sequence of these transducers with two distinct frequencies F1 and F2 provide four transmitting lobes inclined at 30° frontwards, rearwards, left and right. Based on adequate summing of the reception signals, two front/rear and left/right reception lobes are defined in which the echoes are distinguished according to the frequency. The speed of the carrier ship is determined independently of the propagation speed of sound in the water. Furthermore, the plane transmitting base is substantially smaller than an ordinary base which comprises four arrays of inclined transducers.</p> |
