| 摘要 |
The sounding equipment is of the type comprising a pulse generator 1, a pulse transmitter 2, a receiver 3 of a reflected signal (for example from the seabed), and a circuit 7 for processing the reflected signal in order to determine the depth of the sea beneath the ship; a filter circuit 6, comprising a phase-locked loop locked onto the pulse transmission frequency, is introduced between the receiver 3 of the reflected signal and the processing circuit 7 so as to transmit to the processing circuit only those parts of the reflected signal with a frequency corresponding to that of the transmitted pulses. <IMAGE>
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