Ranging apparatus

Claim 1

SONAR PROFILING APPARATUS COMPRISING, IN COMBINATION: A TRANSMITTER HAVING OUTPUT MEANS ACROSS WHICH IS DEVELOPED A SERIES OF PERIODIC PULSES OF ELECTRICAL ENERGY; TRANSDUCER MEANS CONNECTED TO SAID TRANSMITTER OUTPUT MEANS, ELECTRICALLY DRIVEN BY SAID TRANSMITTER, DEVELOPING ACOUSTIC ENERGY CORRESPONDING TO SAID ELECTRIC ENERGY, DIRECTING A RELATIVELY NARROW BEAM OF ACOUSTIC ENERGY TOWARD THE BED OF A BODY OF WATER, RECEIVING ACOUSTIC ENERGY REFLECTED FROM THE BED, AND CONVERTING THE RECEIVED ACOUSTIC ENERGY TO A CORRESPONDING ELECTRIC ENERGY SIGNAL; ACTUATING MEANS CONNECTED TO MECHANICALLY DRIVE SAID TRANSDUCER IN A PREDETERMINED PLANE; A RECEIVER HAVING A SIGNAL INPUT MEANS CONNECTED TO BE ENERGIZED BY THE REFLECTED SIGNAL DEVELOPED BY SAID TRANSDUCER AND HAVING A SIGNAL OUTPUT MEANS ACROSS WHICH A PULSE SIGNAL CORRESPONDING TO THE ACOUSTIC ENERGY REFLECTED FROM SAID BED IS DEVELOPED; A DIFFERENTIATOR HAVING A SIGNAL INPUT MEANS AND OUTPUT MEANS, THE INPUT MEANS CONNECTED TO THE RECEIVER OUTPUT MEANS, SAID DIFFERENTIATOR DEVELOPING A SIGNAL AT ITS OUTPUT MEANS REPRESENTING THE SLOPE OF THE INPUT SIGNAL, SAID SLOPE CHANGING POLARITY WHEN A SIGNAL PEAK IS TRAVERSED; A LEVEL DETECTOR HAVING A SIGNAL INPUT MEANS CONNECTED TO THE DIFFERENTIATOR OUTPUT MEANS, AND AN OUTPUT MEANS ACROSS WHICH THERE IS DEVELOPED AN OUTPUT SIGNAL PULSE OF CONSTANT AMPLITUDE ONLY AS LONG AS THE INPUT SIGNAL TO THE DETECTOR IS LESS THAN A PREDETERMINED LEVEL; AND, A RECORDER HAVING A SIGNAL INPUT MEANS COMNECTED TO BE ENERGIZED BY THE OUTPUT MEANS OF SAID DETECTOR, SAID RECORDER SYNCHRONIZED WITH SAID TRANSMITTER AND SAID TRANSDUCER MEANS AND PROVIDING A LINEAR TIME SCALE THAT IS MARKED WHENEVER SAID DETECTOR PROVIDES A SIGNAL TO THE RECORDER INPUT MEANS.