Patent ID: 6418080
Filing Date: 2002-07-09
Classification: G01S,Y10S

Abstract:
An underwater detection apparatus comprising:a transducer for transmitting and receiving ultrasonic signals into and from the water; a transmitter for generating a transmission signal; a broadband trap circuit connected to the transducer by two conductive lines of a length more than five meters for transferring the transmission signal from the transmitter to the transducer and for passing an echo signal from the transducer; a preamplifier for amplifying the echo signal from the trap circuit; a signal generator for generating signals of a plurality of different signals; a mixer having two inputs with one input receiving the echo signal from the preamplifier and the other input receiving a signal of the signals of a plurality of different frequencies generated from the signal generator for converting the echo signal from the preamplifier into a signal of a specific frequency; a filter for selectively passing the signal of the specific frequency output from the mixer; a main amplifier for amplifying the echo signal from the filter; an A/D converter for converting the echo signal from the amplifier into a digital form; and an indicator for displaying the echo signal from the A/D converter.