Patent attributes
An apparatus for electromagnetically connecting surface equipment to a rotating downhole tool string comprises a plurality of electrical conductors, first and second differential interfaces, and at least one electromagnetic shield. The plurality of electrical conductors have first ends terminating at the surface equipment and second ends terminating at the downhole tool string. The first differential interface is electrically connected to the first ends and the second differential interface is electrically connected to the second ends the electrical conductors. The first and second differential interfaces are adapted to transmit and receive a reference-independent differential signal. The electromagnetic shield surrounds and shields the electrical conductors and is connected to ground at one end. The apparatus is stationary relative to rotation of the tool string. Disclosed is an apparatus for electromagnetically connecting a computer to a rotating downhole tool string comprising a plurality of electrical conductors, first and second differential interfaces, and an electromagnetic shield grounded to a drill rig at one end.
