| 摘要 |
<p>CIRCUIT FOR AUTOMATIC SEABED DISCRIMINATION The invention concerns a circuit for automatic discrimination of the nature of the seabed over which a vessel is passing, and in particular for indicating via an audible or other warning signal when a fishing vessel is above a type of seabed which might damage the fishing net The circuit comprises means responsive to an echo sounder signal to raise an alarm when the amplitude of the second bottom echo component in the echo sounder signal exceeds a selected threshold level. Preferably the analog echosounder signal is subject to threshold discrimination to provide a pulse-form signal which is then processed by a digital logic circuit to isolate the second bottom echo component.</p> |
