Acoustic velocity bore hole logging systems and apparatus

Claim 1

IN A SYSTEM FOR MEASURING THE ACOUSTIC VELOCITY OF EARTH FORMATIONS ADJACENT A BOREHOLE, THE COMBINATION OF AN ACOUSTIC PULSE TRANSMITTER MOVABLY POSITIONED IN SAID BOREHOLE FOR GENERATING AND TRANSMITTING TO SAID FORMATIONS A TRAIN OF ACOUSTIC PULSES AND FOR CONCURRENTLY GENERATING A TRAIN OF SYNCHRONIZING PULSES, A GENERATOR FOR PRODUCING A SIGNAL OUTPUT WAVEFORM THE AMPLITUDE OF WHICH VARIES MONOTONICALLY AS A FUNCTION OF TIME FOR A PREDETERMINED TIME INTERVAL, MEANS CONNECTED TO RECEIVE SAID SYNCHRONIZING PULSES AND FOR INITIATING GENERATION OF SAID WAVEFORM RESPONSIVE TO EACH SAID SYNCHRONIZING PULSE, FIRST AND SECOND ACOUSTIC ENERGY RECEIVERS MOVABLY POSITIONED IN SAID BOREHOLE AND SPACED DIFFERENT FIXED DISTANCES LONGITUDINALLY OF THE BOREHOLE FROM EACH OTHER AND FROM SAID TRANSMITTER, FIRST AND SECOND MEANS RESPECTIVELY ASSOCIATED WITH THE FIRST AND SECOND RECEIVERS AND RESPONSIVE TO THE OUTPUT OF SAID GENERATOR AND EACH ACQUIRING AND STORING A SIGNAL LEVEL WHICH IS PROPORTIONAL TO THE INSTANTANEOUS MAGNITUDE OF SAID WAVEFORM