| 摘要 |
PURPOSE:To shorten a measurement time by finding a measurement range which is enough to acquire an interface in a sonar scanning range previously, and detecting only an echo from the measurement range at the time of actual interface detection. CONSTITUTION:A switch SW is placed on its (x) side to send a beam at right angles to the interface W and a signal detecting circuit 3 and a correlation processing circuit 6 finds the depth of the interface W; and then a prediction gate setting circuit 7 predicts a sampling range (measurement range D') for depth and the range is set as a prediction gate signal in the circuit 3. Then the SW is switched to its (y) side to perform the actual interface detection. Namely, when the beam is sent at a point t1 with the output of a sent pulse Q1, the circuit 3 begins to sample the data from an A/D converter 2 at a point t2. The echo from the interface W is received and amplified 1 at a point t3, A/D-converted 2, and inputted to the circuit 3. Then when the sampling is completed at a point t4, a trigger generating circuit 8 outputs a next exciting pulse Q2. |
