M.A. Akafyev – Post-graduate Student, Department «Electronic Instruments and Devices», Yuri Gagarin State Technical University of Saratov
A.V. Melnikov – Ph. D. (Eng.), Main Designer, LCC «Geophysmash» (Saratov)
A.A. Zakharov – Dr. Sc. (Eng.), Professor, Head of Department «Electronic Instruments and Devices», Yuri Gagarin State Technical University of Saratov
Modern downhole equipment requires data transfer in digital form and at high speed to a surface acquisition station. At present, a virtually single telemetry line between the downhole equipment and the surface acquisition system is a logging cable. It has its frequency response and operating frequency range.
The paper deals with one of the ways to improve geophysical equipment in the part of transmitting information sequences from downhole equipment to geophysical station. One way to increase the line capacity is based on matching the n bits of the information sequence with 2n values of the amplitude of the sinusoidal signal. Such a method allows one to increase several times the data transmission speed due to the fact that during one period of the carrier signal several data bytes are transmitted. Schematic diagram of the implementation of the hardware part of the transmitter of the downhole tool is given. The operation of the main parts of the electronic circuit of the transmitter is described. The results of tests, the proposed method of information transfer are presented.
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