Digital-to-analog combinational converters

Claim 1

APPARATUS FOR PRODUCING OUTPUT VOLTAGES REPRESENTATIVE OF THE DIFFERENCE BETWEEN TWO SHAFT POSITIONS LOCATED AT REMOTE POINTS COMPRISING MEANS FOR RECEIVING SPACIAL VOLTAGES REPRESENTATIVE OF THE POSITION OF A FIRST SHAFT, MEANS FOR RECEIVING DIGITAL CODE GROUPS REPRESENTATIVE OF THE POSITION OF A SECOND SHAFT, VOLTAGE APPROXIMATION MEANS RESPONSIVE TO A PLURALITY OF THE MORE SIGNIFICANT CODE DIGITS FOR SIMULTANEOUSLY WEIGHTING SAID SIGNIFICANT DIGITS AND MODULATING SAID SPACIAL VOLTAGES IN ACCORDANCE WITH SAID WEIGHTING TO PRODUCE VOLTAGE MAGNITUDES INDICATIVE OF THE SHAFT POSITION DIFFERENCE TO A FIRST APPROXIMATION, AND LINEAR EVALUATION MEANS RESPONSIVE TO THE REMAINING CODE DIGITS FOR RECEIVING SAID FIRST APPROXIMATION VOLTAGES AND SIMULTANEOUSLY WEIGHTING SAID REMAINING CODE DIGITS TO ADJUST THE MAGNITUDE OF SAID FIRST APPROXIMATION VOLTAGES IN ACCORDANCE WITH SAID EVALUATION WEIGHTING TO PRODUCE OUTPUT VOLTAGES INDICATIVE OF THE SHAFT POSITION DIFFERENCE.