| 摘要 |
PURPOSE:To measure a position with a high precision even if various reflected echoes exist, by eliminating the signal of a part having a disturbed phase by a phase difference gate control circuit. CONSTITUTION:Receiving signals are received by receiving elements 16-18 and are amplified in preamplifiers 19-21 and are converted to pulses by pulse circuits 22-24. A direct distance measuring circuit 25 counts the period from the transmission reference of a sounding body to the reception time with clocks corresponding to the underwater acoustic velocity to attain the distance. A phase difference gate control circuit 29 generates a gate part of a time corresponding to the number of mountains in a part, where the waveform is not disturbed, set by a mountain number set counter 30 as shown in Fig. (c). The period from a time D to a time E in Fig. (c) is a gate used for measurement, and the succeeding part is eliminated by the counter 30 because the phase is distrubed. |
