| 摘要 |
PURPOSE:To display the middle and lower positions of a net on a display screen, by transmitting a net position signal from an underwater search device when transponders receive underwater search signals and displaying the net position with the underwater search device when said device receives the net position signals. CONSTITUTION:The underwater search signal transmitted from a scanning sonar arrives at the transponders 12, 12...; 13, 13... installed in the middle and lower positions of a net 14 cast into the sea from a roundhaul netter. The transponders 12, 12...; 13, 13... receive the incoming underwater search signals respectively and amplify the received underwater search signals with respective amplifiers 8. The amplified underwater search signals are decided of whether the signals are the underwater search signal from the scanning sonar of the own ship or not by the respective comparators 9 in the transponders 12, 12...; 13, 13.... The comparators 9 transmit the compared output to drive a single shot pulse generator 10 when they decide that the signals are the underwater search signal from the scanning sonar of the own ship. The generator 10 outputs the single shot pulse having a pulse width of a prescribed time to a transmitter 11 in response to the compared output. |
