Apparatus for measuring resistance at the end of a long cable

Claim 1

APPARATUS FOR REMOTELY MEASURING RESISTANCE COMPRISING, A CABLE HAVING FIRST, SECOND AND THIRD CONDUCTORS WITH DISTRIBUTED SHUNT RESISTANCE THEREBETWEEN, A FIRST RESISTANCE HAVING AN UNKNOWN VALUE CONNECTED BETWEEN SAID FIRST AND SECOND CONDUCTORS AT ONE END OF THE CABLE, SAID THIRD CONDUCTOR HAVING AN OPEN CIRCUIT TERMINATION AT SAID ONE END OF SAID CABLE, AN ELECTRIC CIRCUIT COMPRISING A SECOND RESISTANCE, CONNECTED BETWEEN A FIRST AND SECOND JUNCTION POINT, A THIRD RESISTANCE CONNECTED BETWEEN SAID SECOND AN D A THIRD JUNCTION POINT, AND A FOURTH RESISTANCE CONNECTED BETWEEN SAID THIRD AND A FOURTH JUNCTION POINT, A CURRENT INDICATING MEANS CONNECTED BETWEEN SAID SECOND AND FOURTH JUNCTION POINTS, A SOURCE OF DIRECT CURRENT CONNECTED BETWEEN SAID FIRST AND THIRD JUNCTION POINTS, AND CONNECTING MEANS ON THE OTHER END OF SAID CABLE CONNECTING SAID FIRST CONDUCTOR TO SAID FIRST JUNCTION POINT AND SAID SECOND CONDUCTOR TO SAID FOURTH JUNCTION POINT FORMING WITH SAID ELECTRIC CIRCUIT A WHEATSTONE BRIDGE, SAID CABLE INTRODUCING AN UNDESIRED CABLE SHUNT RESISTANCE IN AN ARM OF SAID BRIDGE INCLUDING SAID FIRST AND SECOND CONDUCTORS AND SAID FIRST RESISTANCE, SAID CONNECTING MEANS ALSO CONNECTING SAID THIRD CONDUCTOR TO SAID THIRD JUNCTION POINT INTRODUCING A COMPENSATING CABLE SHUNT RESISTANCE IN AN ARM OF SAID BRIDGE INCLUDING SAID FOURTH RESISTANCE.