Transducer system having a variable characteristic discriminator

Claim 1

A NON-CONTACT SYSTEM FOR TRANSDUCING A VARIABLE TO BE MEASURED INCLUDING PORTABLE PICKUP MEANS ADAPTED TO BE HAND HELD BY A USER IN OPERATIVE POSITION RELATIVE TO A SOURCE OF SAID VARIABLE, MEANS CONNECTED TO SAID HAND HELD PICKUP MEANS FOR PRODUCING A CARRIER FREQUENCY MODULATED IN RESPONSE TO VARIATIONS IN SAID VARIABLE, SAID CARRIER FREQUENCY EXPERIENCING SUBSTANTIAL AND RAPID VARIATIONS DURING OPERATION DUE TO MOVEMENT OF THE PICKUP MEANS IN THE HANDS OF THE USER, BEAT OSCILLATOR MEANS, MIXER MEANS FOR MIXING SAID FREQUENCY MODULATED CARRIER AND THE SIGNAL FROM SAID BEAT OSCILLATOR TO PROVIDE AN I.F. SIGNAL, DISCRIMINATOR MEANS FOR DETECTING SAID I.F. SIGNAL, AND AUTOMATIC FREQUENCY CONTROL MEANS FOR MAINTAINING SAID I.F. SIGNAL AT A CONSTANT FREQUENCY, SAID AUTOMATIC FREQUENCY CONTROL MEANS BEING RESPONSIVE TO A SIGNAL FROM SAID DISCRIMINATOR MEANS, SAID DISCRIMINATOR MEANS HAVING AN OVERALL DISCRIMINATOR CHARACTERISTIC HAVING A HIGH SLOPE OVER THE RANGE OF DEVIATION NORMALLY CAUSED BY THE VARIATION OF SAID VARIABLE AND A LOWER SLOPE OVER A LARGER DEVIATION RANGE WHICH IS CONSIDERABLY GREATER THAN THE HIGH SLOPE DEVIATION RANGE.