Seismic system using a slotted disc source producing a binary code

Claim 1

APPARATUS FOR MEASURING THE TRAVEL TIME OF SEISMIC WAVES BETWEEN THE EARTH''S SURFACE AND A GEOPHONE SPACED THEREFROM, COMPRISING: PULSE GENERATING MEANS FOR PRODUCING FIRST AND SECOND TIMING PULSE TRAINS OF EQUALLY TIME-SPACED ELECTRICAL PULSES, FIRST AND SECOND CODED PULSE TRAINS OF TIMESPACED PULSES HAVING A PSEUDO-RANDOM TIME DISTRIBUTION, EACH PULSE IN SAID FIRST CODED PULSE TRAIN BEING CONCOMITANT WITH A PULSE IN SAID FIRST TIMING PULSE TRAIN AND EACH PULSE IN SAID SECOND CODED PULSE TRAIN BEING CONCOMITANT WITH A PULSE IN SAID SECOND TIMING PULSE TRAIN, SAID PULSE GENERATING MEANS FURTHER INCLUDING MEANS FOR ADJUSTABLY DELAYING ONE OF SAID CODED PULSE TRAINS RELATIVE TO THE OTHER OF SAID CODED PULSE TRAINS; FIRST CIRCUIT MEANS CONNECTED TO SAID PULSE GENERATING MEANS FOR PRODUCING A SINUSOIDAL OUTPUT SIGNAL HAVING ONE PHASE RESPONSIVE TO CONCOMITANT PULSES OF SAID FIRST CODED PULSE TRAIN AND FIRST TIMING PULSE TRAIN, AND HAVING THE OPPOSITE PHASE RESPONSIVE TO A PULSE FROM SAID FIRST TIMING PULSE TRAIN UNACCOMPANIED BY A PULSE FROM SAID FIRST CODED PULSE TRAIN; TRANSDUCER MEANS CONNECTED TO SAID FIRST CIRCUIT MEANS FOR PRODUCING SEISMIC WAVES RESPONSIVE TO THE OUTPUT SIGNAL THEREOF: ELECTRICAL TERMINAL MEANS FOR CONNECTION TO SAID GEOPHONE;