Asynthronous pulse telemetry system and method

摘要

The specification discloses a technique for transmitting randomized pulses generated by a downhole well logging device through a cable to an uphole station. Circuitry is provided within the logging device to receive the randomized pulses. A clock generates a clock signal having a periodic clock frequency. A gate is connected to the output of the clock for selectively gating the clock signal. Circuitry is responsive to the reception of the randomized pulses for operating the gate for a prescribed interval to delete predetermined portions of the clock signal. The output of the gate is divided to generate a series of pulses having periods representative of the reception of the randomized pulses. The series of pulses is transmitted through the cable to the uphole station. Circuitry located at the uphole station utilizes phase lock loop circuitry to reconstruct representations of the randomized pulses in response to the series of pulses.