| 摘要 |
PURPOSE:To measure a distance from a depth of a sea, etc. to the sea surface without an error, by opening a gate which outputs a distance signal only in case when ultrasonic receiving pulse width is wider than transmitted pulse width. CONSTITUTION:A transmitted ultrasonic wave reflected by the sea surface is received by a transmitter and receiver 2. In case when pulse width of this received wave is wider than pulse width of a transmitted wave, a pulse width deciding circuit 7 decides reception of a reflected wave from the sea surface on which complicated reflected waves are superposed, and opens an output gate open circuit 9. Subsequently, an output from the circuit 9 of a time measuring output between transmission and reception corresponding to a distance to the sea surface, which is stored in a storing circuit 8, and its cut-off are controlled. According to this constitution, a distance measurement based on erroneous reception is prevented, and a distance from a depth of the sea or the sea bottom, etc., to the sea surface is measured exactly without an error. |
