| 摘要 |
PURPOSE:To observe not only a wave crest and a period but also an advance direction of a wave by setting a directional angle of a transmitting and receiving beam to a wide angle by setting a roughly right above position as a start point, and also setting said angle to a sector whose beam width has become small. CONSTITUTION:As for an ultrasonic transmitter and receiver 1 installed to the sea bottom 2, that which has set a transmitting and receiving beam 3 to a sector beam by setting its roughly right above position as a start point is used. When the sea surface reflected wave is received by the transmitter and receiver 1, its receiving signal is sent to a receiving circuit 12 through a transmission and reception switching circuit 11. Also, the receiving circuit 12 converts the receiving signal which has eliminated a noise, to a voltage of a suitable level and applies it to an electric conductive rail 52, and a synchronizing circuit 13 forms a synchronizing pulse, when a recording pen 51 has come to a recording start position, and starts a transmitting circuit 10. In this state, when the recording pen 51 is made to execute one reciprocating motion at every one pulse oscillation, a recording image is obtained on an electrostatic recording paper 4. |
