Computing device for computing the logarithm of the ratio of two voltages

Claim 1

APPARATUS FOR COMPUTING THE LOGARITHM OF THE RATIO OF TWO VOLTAGES COMPRISING A SOURCE OF VOLTAGE B; A SOURCE OF VOLTAGE A; COMPARATOR CIRCUIT MEANS HAVING TWO INPUT TERMINALS AND AN OUTPUT TERMINAL FOR PROVIDING AN OUTPUT SIGNAL AT SAID OUTPUT TERMINAL WHEN THE MAGNITUDES OF VOLTAGES PROVIDED AT SAID INPUT TERMINALS BEAR A PREDETERMINED RELATIONSHIP TO EACH OTHER; A FIRST PLURALITY OF ATTENUATOR CIRCUITS CONNECTED IN SERIES CIRCUIT RELATIONSHIP BETWEEN SAID SOURCE OF VOLTAGE B AND ONE OF SAID INPUT TERMINALS OF SAID COMPARATOR CIRCUIT MEANS, SAID ATTENUATORS HAVING PRESELECTED ATTENUATION COEFFICIENTS; A SECOND PLURALITY OF ATTENUATOR CIRCUITS CONNECTED IN SERIES CIRCUIT RELATIONSHIP BETWEEN SAID SOURCE OF VOLTAGE A AND THE OTHER OF SAID INPUT TERMINALS OF SAID COMPARATOR CIRCUIT MEANS, SAID ATTENUATORS HAVING PRESELECTED ATTENUATION COEFFICIENTS; A PLURALITY OF SWITCH MEANS FOR SELECTIVELY COMPLETING AND OPENING INDIVIDUAL LOW RESISTANCE PATHS IN PARALLEL CIRCUIT RELATIONSHIP WITH EACH ATTENUATOR OF SAID FIRST AND SECOND PLURALITY OF ATTENUATOR CIRCUITS; MEANS FOR CONTROLLING SAID SWITCH MEANS TO OPEN EACH OF SAID LOW RESISTANCE PATHS SINGLY AND IN AS PREDETERMINED SEQUENCE; AND MEANS RESPONSIVE TO THE OUTPUT VOLTAGE OF SAID COMPARATOR CIRCUIT MEANS FOR MAINTAINING SELECTED ONES OF SAID LOW RESISTANCE PATHS OPEN TO ALLOW A PERMUTATION OF SAID ATTENUATOR CIRCUITS TO ACTIVELY REMAIN IN SAID SERIES CIRCUITS, THE ATTENUATORS ACTIVELY REMAINING HAVING COEFFICIENTS THE SUM OF WHICH IS REPRESENTATIVE OF THE LOGARITHM OF THE RATIO OF A/B.