Angular resolver

Claim 1

AN ANGLE RESOLVER COMPRISING A FIRST DISC FORMED OF ELECTRICALLY INSULATING MATERIAL, A FIRST COIL PRINTED ON ONE SURFACE OF SAID FIRST DISC, SAID FIRST COIL HAVING A PREDETERMINED NUMBER OF TURNS, A SECOND COIL PRINTED ON THE OPPOSITE SURFACE OF SAID FIRST DISC AND FIXED IN SPACE QUADRATURE WITH FIRST COIL, SAID SECOND COIL HAVING THE SAME NUMBER OF TURNS AS SAID FIRST COIL; A SECOND DISC FORMED OF ELECTRICALLY INSULATING MATERIAL, A THRID COIL PRINTED ON ONE SURFACE OF SAID SECOND DISC, SAID THIRD COIL HAVING THE SAME NUMBER OF TURNS AS SAID FIRST COIL AND A FOURTH COIL PRINTED ON THE OPPOSITE SURFACE OF SAID SECOND DISC IN SPACE QUADRATURE WITH SAID THIRD COIL, SAID FOURTH COIL HAVING THE SAME NUMBER OF TURNS AS SAID THIRD COIL, SAID FIRST AND SAID SECOND DISCS BEING CONCENTRICALLY MOUNTED AND RELATIVELY ROTATABLE WITH RESPECT TO ONE ANOTHER, DRIVE SIGNAL MEANS FOR APPLYING TO SAID FIRST COIL A SIGNAL INCLUDING A SQUARE WAVE COMPONENT AT A FIRST PRDETERMINED FREQUENCY AND FOR APPLYING TO SAID SECOND COIL A SIGNAL INCLUDING A SQUARE WAVE AT SAID SAME FIRST PREDETERMINED FREQUENCY BUT DISPLACED NINETY ELECTRICAL DEGREES IN PHASE FROM SAID SQUARE WAVE APPLIED TO SAID FIRST COIL; PHASE DETECTOR MEANS CONNECTED TO ONE OF SAID THIRD AND FOURTH COILS AND TO SAID DRIVE SIGNAL MEANS FOR PROVIDING AN OUTPUT SIGNAL INDICATIVE OF THE DIFFERENCE IN PHASE BETWEEN THE SQUARE WAVE COMPONENT AT SAID FIRST PREDETERMINED FREQUENCY OF SAID SIGNALS APPLIED TO SAID FIRST AND SECOND COILS AND THE SIGNALS OF SAID FIRST PREDETERMINED FREQUENCY ON SAID THIRD AND FOURTH COILS.