Electrical position-encoding apparatus and systems including such apparatus

Claim 1

ELECTRICAL POSITION ENCODING APPARATUS COMPRISING A VARIABLE RELUCTANCE TRANSFORMER THAT COMPRISES A PRIMARY WINDING, A PLURALITY OF SECONDARY WINDINGS, A PAIR OF FERROMAGNETIC CORES, A SERIES OF FERROMAGNETIC TEETH ON EACH SAID CORE, THE TWO SERIES BEING MUTUALLY OPPOSED AND OF DIFFERENT TOOTH-PITCH THUS GIVING A CYCLIC RELATIONSHIP BETWEEN OPPOSING TEETH THERE BEING AT LEAST ONE CYCLE IN EACH SAID SERIES, ONE SAID CORE BEING MOVABLE RELATIVE TO THE OTHER TO VARY INDUCTIVE COUPLING BETWEEN THE PRIMARY AND EACH SECONDARY WINDING, CYCLIC VARIATION OF SAID INDUCTIVE COUPLING BEING PRODUCED BY CONTINUOUS MOVEMENT OF THE TEETH OF SAID ONE CORE PAST EACH OF THE TEETH OF THE OTHER CORE, AND SAID SECONDARY WINDINGS BEING POSITIONED WITH RESPECT TO EACH OTHER SO THAT, OWING TO THE DIFFERENT TOOTH-PITCHES OF THE CORES AND THE CONSEQUENT CYCLIC TOOTH RELATIONSHIP, SAID CYCLIC VARIATION OF INDUCTIVE COUPLING IS OF DIFFERENT PHASE OF EACH SECONDARY WINDING; AND CIRCUIT MEANS INCLUDING MEANS FOR DERIVING FROM SIGNALS INDUCED IN THE SECONDARY WINDINGS WHEN THE PRIMARY WINDING IS EXCITED WITH ALTERNATING CURRENT AT LEAST ONE PAIR OF SIGNALS WHICH HAVE AMPLITUDES THAT VARY CYCLICALLY IS ACCORDANCE WITH THE CYCLIC VARIATIONS OF SAID