Composite signal generating means for multiple-speed positional servo system

Claim 1

A DUAL-SPEED APPARATUS FOR INDICATING THE ANGULAR POSITION OF A ROTATABLE DEVICE, SAID APPARATUS COMPRISING (A) MEANS COUPLED TO SAID ROTATABLE DEVICE AND INCLUDING A FIRST OUTPUT ROTOR FOR PRODUCING A FIRST OUTPUT SIGNAL OF AN AMPLITUDE AND PHASE RELATIVE TO A REFERENCE SIGNAL DEPENDENT UPON THE ANGULAR POSITION OF SAID FIRST OUTPUT ROTOR RELATIVE TO THAT OF SAID ROTATABLE DEVICE, SAID FIRST OUTPUT SIGNAL HAVING A PREDETERMINED NUMBER OF PHASE CHANGES RELATIVE TO SAID REFERENCE SIGNAL PER EACH REVOLUTION OF SAID ROTATABLE DEVICE WHEN SAID FIRST OUTPUT ROTOR IS MAINTAINED IN A FIXED ANGULAR POSITION; (B) MEANS COUPLED TO SAID ROTATABLE DEVICE AND INCLUDING A SECOND OUTPUT ROTOR FOR PRODUCING A SECOND OUTPUT SIGNAL OF AN AMPLITUDE AND PHASE RELATIVE TO SAID REFERENCE SIGNAL DEPENDENT UPON THE ANGULAR POSITION OF SAID SECOND OUTPUT ROTOR RELATIVE TO THAT OF SAID ROTATABLE DEVICE, SAID SECOND OUTPUT SIGNAL HAVING AN EVEN INTEGRAL NUMBER OF PHASE CHANGES RELATIVE TO SAID REFERENCE SIGNAL FOR EACH PHASE CHANGE OF SAID FIRST OUTPUT SIGNAL RELATIVE TO SAID REFERENCE SIGNAL WHEN SAID SECOND OUTPUT ROTOR IS MAINTAINED IN A FIXED ANGULAR POSITION; (C) AN ELECTRICAL NETWORK INCLUDING FIRST, SECOND AND THIRD INPUT TERMINALS, SAID FIRST AND SECOND INPUT TERMINALS BEING CONNECTED TO OPPOSITE EXTREMITIES OF SAID FIRST OUTPUT ROTOR AND SAID FIRST AND THIRD INPUT TERMINALS BEING CONNECTED TO OPPOSITE EXTREMITIES OF SAID FIRST OUTPUT ROTOR AND SAID FIRST AND THIRD INPUT TERMINALS BEING CONNECTED TO OPPOSITE EXTREMITIES OF SAID SECOND OUTPUT ROTOR WHEREBY THE TOTAL VOLTAGE GENERATED ACROSS SAID FIRST AND SECOND OUTPUT ROTORS APPEARS ACROSS SAID SECOND AND THIRD INPUT TERMINALS; FIRST AND SECOND OUTPUT TERMINALS, SAID FIRST OUTPUT TERMINAL BEING CONNECTED TO SAID SECOND INPUT TERMINAL; A VOLTAGE DROPPING RESISTOR CONNECTED FROM SAID THIRD INPUT TERMINAL TO SAID SECOND OUTPUT TERMINAL; MEANS HAVING A LOW INTERNAL IMPEDANCE COMPARED TO THE OHMIC VALUE OF SAID VOLTAGE DROPPING RESISTOR FOR PRODUCING A POTENTIAL SUBSTANTIALLY EQUAL TO THE VOLTAGE ACROSS SAID FIRST AND SECOND INPUT TERMINALS AT A FIRST JUNCTION IN RESPONSE TO A POTENTIAL OF POSITIVE POLARITY APPEARING AT SAID FIRST INPUT TERMINAL RELATIVE TO SAID SECOND INPUT TERMINAL; MEANS HAVING A LOW INTERNAL IMPEDANCE COMPARED TO THE OHMIC VALUE OF SAID VOLTAGE DROPPING RESISTOR FOR PRODUCING A POTENTIAL SUBSTANTIALLY EQUAL TO THE VOLTAGE ACROSS SAID FIRST AND SECOND INPUT TERMINALS AT A SECOND JUNCTION IN RESPONSE TO A POTENTIAL OF NEGATIVE POLARITY APPEARING AT SAID FIRST INPUT TERMINAL RELATIVE TO SAID SECOND INPUT TERMINAL; AND FIRST AND SECOND UNIDIRECTIONALLY CONDUCTING DEVICES CONNECTED FROM SAID FIRST AND SECOND JUNCTIONS, RESPECTIVELY, TO SAID SECOND OUTPUT TERMINAL, SAID FIRST UNIDIRECTIONALLY CONDUCTING DEVICE BEING POLED TO ALLOW CURRENT FLOW TOWARDS SAID SECOND OUTPUT TERMINAL AND SAID SECOND UNIDIRECTIONALLY CONDUCTING DEVICE BEING POLED TO ALLOW CURRENT FLOW AWAY FROM SAID SECOND OUTPUT TERMINAL THEREBY TO GENERATE A COMPOSITE ERROR SIGNAL REPRESENTATIVE OF THE SUM OF SAID FIRST AND SECOND OUTPUT SIGNALS DURING INTERVALS THAT SAID FIRST AND SECOND OUTPUT SIGNALS ARE OF THE SAME PHASE AND REPRESENTATIVE OF SAID FIRST OUTPUT SIGNAL ONLY DURING INTERVALS THAT SAID FIRST AND SECOND OUTPUT SIGNALS ARE OF OPPOSITE PHASE; AND (D) MEANS MECHANICALLY COUPLED TO SAID FIRST AND SECOND OUTPUT ROTORS AND RESPONSIVE TO SAID COMPOSITE ERROR SIGNAL AND SAID REFERENCE SIGNAL FOR POSITIONING SAID FIRST AND SECOND OUTPUT ROTORS TO REDUCE SAID ERROR SIGNAL TO ZERO AMPLITUDE THEREBY TO INDICATE THE ANGULAR POSITION OF SAID ROTATABLE DEVICE.