Well signaling system

Claim 1

IN APPARATUS FOR OIL WELL LOGGING, WHILE DRILLING, WITH A CONTINUOUS METALLIC PIPE DRILLING STRING, A TRANSMITER INDUCTIVELY COUPLED TO SAID PIPE DRILLING STRING AND DISPOSED AT THE BOTTOM OF SAID OIL WELL FOR GENERATING AND TRANSMITTING SUCCESSIVE PULSES OF ALTERNATE POLARITY EACH HAVING SUBSTANTIALLY UNIFORM AMPLITUDE, EACH PULSE HAVING A DURATION THAT IS RELATIVELY SHORT COMPARED TO THE TIME INTERVAL BETWEEN TWO SUCCESSIVE PULSES, SAID TIME INTERVAL BETWEEN EACH TWO SUCCESSIVE PULSES BEING REPRESENTATIVE IN PREDETERMINED SEQUENCE OF DIFFERENT PHYSICAL DATA TO BE TRANSMITTED SEQUENCE OF DIFFERENT PHYSICAL DATA TO BE WELL, EACH BEING INDUCTIVELY COUPLED TO SAID PIPE DRILLING STRING AND INCLUDING AN AMPLIFIER RESPONSIVE TO TRANSMITTED UNIFORM AMPLITUDE PULSES HAVING AN AMPLITUDE EXCEEDING A PREDETERMINED THRESHOLD LEVEL, SAID AMPLIFIER IN EACH REPEATER STATION DEVELOPING AN AMPLIFIED UNIFORM AMPLITUDE OUTPUT PULSE IN RESPONSE TO A PULSE EXCEEDING SAID THRESHOLD LEVEL.