Phase repeater servo

Claim 1

IN COMBINATION (A) AN ELECTROMECHANICAL RESOLVER ADAPTED TO PRODUCE AN ELECTRICAL OUTPUT S108 IN A PICK-UP COIL AT A FIRST FREQUENCY WHEN EXCITED WITH A FIRST REFERENCE SIGNAL S104 AT SAID FREQUENCY HAVING A FIRST PHASE, DESIGNATED THE REFERENCE PHASE, AND A SECOND REFERENCE SIGNAL S106 HAVING A SECOND PHASE SUBSTANTIALLY DISPLACED FROM SAID REFERENCE PHASE, SAID OUTPUT S108 HAVING A PHASE WHICH VARIES FROM SAID REFERENCE PHASE AS THE INPUT ANGLE 0, WHICH ANGLE MEASURES THE ROTATION OF SAID COIL RELATIVE TO A REFERENCE POSITION. (B) A SOURCE 114 OF A HIGH FREQUENCY WAVE S113, (C) COUNTDOWN MEANS 112 FOR PRODUCING SAID REFERENCE SIGNALS S104 AND S106 PRECISELY LOCKED IN PHASE TO SAID HIGH FREQUENCY WAVE S113, (D) COUNTDOWN MEANS 112 FOR PRODUCING A THIRD REFERENCE SIGNAL S116 PRECISELY LOCKED IN PHASE TO SAID HIGH FREQUENCY WAVE, SAID THIRD SIGNAL HAVING AN INTERMEDIATE FREQUENCY WHICH IS AN IMPROPER RATIONAL FRACTION OF SAID FIRST FREQUENCY, (E) CONTROLLED MEANS 120 FOR GENERATING A FIRST VARIABLE FREQUENCY SIGNAL S128 HAVING A FREQUENCY IN THE NEIGHBORHOOD OF SAID INTERMEDIATE FREQUENCY, (F) SCALING MEANS 122 FOR GENERATING A SECOND VARIABLE FREQUENCY SIGNAL S124, PHASE-LOCKED TO SAID FIRST VARIABLE FREQUENCY SIGNAL S128 AT THE FREQUENCY OBTAINED BY DIVIDING SAID FIRST VARIABLE FREQUENCY BY SAID IMPROPER RATIONAL FRACTION, (G) MEANS 126 FOR COMPARING SAID SECOND VARIABLE SIGNAL S124 WITH SAID OUTPUT SIGNALS S108 AND FOR GENERATING AN ERROR SIGNAL S127 WHICH DEPENDS UPON THE PHASE DIFFERENCE BETWEEN SAID SECOND VARIABLE SIGNAL S124 AND SAID OUTPUT SIGNAL S108, (H) SAID CONTROLLED MEANS 120 RESPONSIVE TO SAID ERROR SIGNAL S127 FOR CHANGING SAID FREQUENCY OF SAID FIRST VARIABLE SIGNAL S128 IN THE DIRECTION TO MINIMIZE THE PHASE DIFFERENCE BETWEEN SAID SECOND VARIABLE SIGNAL S124 AND SAID OUTPUT SIGNAL S108, (I) MEANS 129 FOR COMPARING SAID FIRST VARIBALE FREQUENCY SIGNAL S128 WITH SAID THIRD REFERENCE SIGNAL S116 AND FOR GENERATING A SIGNAL S131, COMPRISING A DIFFERENCE SIGNAL S142 AND HIGHER FREQUENCY MODULATION PRODUCTS, WHERE SAID SIGNAL S142 DEPENDS UPON THE PHASE DIFFERENCE BETWEEN SAID FIRST VARIABLE SIGNAL S128 AND SAID THIRD REFERENCE SIGNAL S116, (J) MEANS 132 FOR SEPARATING SAID DIFFERENCE SIGNAL S142 FROM SAID HIGHER FREQUENCY MODULATION PRODUCTS, AND (K) MEANS 140 FOR GENERATING AN INCREMENTAL OUTPUT SIGNAL WHEN SAID DIFFERENCE SIGNAL S142 CROSSES A PREDETERMINED LEVEL.