Electronic gaging device with linear output characteristics utilizing a series network of diodes as part of the metering circuit

Claim 1

MEASURING MEANS WHOSE REACTANCE IS AFFECTED BY THE PRESENCE OF EXTERNAL METALLIC MEMBERS WITHIN ITS FIELD OF INFLUENCE COMPRISISNG: REACTANCE PICK-UP MEANS FOR PROVIDING A SIGNAL INDICATIVE OF THE SPACING BETWEEN SAID PICK-UP MEANS AND A SPACED METALLIC MEMBER WITHIN ITS FIELD OF INFLUENCE; A BRIDGE HAVING FIRST, SECOND, AND THIRD IMPEDANCE MEANS CONNECTED IN SERIES WITH SAID REACTANCE PICK-UP MEANS TO FORM A LOOP HAVING TWO PAIRS OF OPPOSED JUNCTIONS; A REGULATED A.C. SOURCE CONNECTED TO A FIRST SAID PAIR OF OPPOSED JUNCTIONS; AN UNBALANCE CURRENT METERING CIRCUIT CONNECTED BETWEEN THE OTHER SAID PAIR OF OPPOSED JUNCTIONS, SAID UNBALANCE CIRCUIT INCLUDING: CURRENT RESPONSIVE MEANS; A PAIR OF RECTIFIER MEANS ARRANGED IN OPPOSITELY POLED RELATIONSHIP, ONE OF SAID PAIR BEING CONNECTED IN SERIES WITH A DIFFERENT SIDE OF SAID CURRENT RESPONSIVE MEANS IN SAID METERING CIRCUIT; A FIRST TWO-TERMINAL R.C. FILTERING NETWORK HAVING ONE TERMINAL CONNECTED BETWEEN A POINT OF SAID METERING CIRCUIT COMMON TO A SAID RECTIFIER MEANS AND SAID CURRENT RESPONSIVE MEANS AND THE OTHER TERMINAL CONNECTED TO SAID A.C. SOURCE; AND A SECOND TWO-TERMINAL R.C. FILTERING NETWORK HAVING ONE TERMINAL CONNECTED BETWEEN A POINT OF SAID METERING CIRCUIT COMMON TO THE OTHER SAID RECTIFIER MEANS AND SAID CURRENT RESPONSIVE MEANS AND THE OTHER TERMINAL CONNECTED TO THE SAID A.C. SOURCE; A PLURALITY OF SERIES CONNECTED, LIKE POLED DIODES ARRANGED TO OPERATE IN THEIR NONLINER CHARACTERISTIC REGION CONNECTED BETWEEN ONE OF SAID RECTIFIER MEANS AND SAID CURRENT RESPONSIVE MEANS, AND A VARIABLE RESISTANCE DEVICE CONNECTED IN PARALLEL WITH EACH OF SAID DIODES.