Phase difference speed control system

Claim 1

IN COMBINATION IN A SYSTEM FOR PRODUCING A REFERENCE SIGNAL TO CONTROL THE SPEED OF A MOTOR MEANS TO DRIVE A RECORDING MEDIUM WHEREIN THE RECORDING MEDIUM HAS CONTAINED THEREON A FIRST REFERENCE SIGNAL, FIRST MEANS OPERATIVELY COUPLED TO THE RECORDING MEDIUM FOR DETECTING THE FIRST REFERENCE SIGNAL RECORDED ON THE MEDIUM, FILTER MEANS OPERATIVELY COUPLED TO THE FIRST MEANS AND HAVING A SELECTED BANDPASS TO PASS THE FIRST REFERENCE SIGNAL WHEN THE FIRST REFERENCE SIGNAL HAS FREQUENCY VALUES RELATED TO THE DESIRED SPEED OF MOVEMENT OF THE RECORDING MEDIUM AND TO BLOCK THE FIRST REFERENCE SIGNAL WHEN THE FIRST REFERENCE SIGNAL HAS FREQUENCY VALUES UNRELATED TO THE DESIRED SPEED, SECOND MEANS OPERATIVELY COUPLED TO THE MOTOR MEANS FOR PRODUCING A SECOND REFERENCE SIGNAL HAVING CHARACTERISTICS IN ACCORDANCE WITH THE SPEED OF THE MOTOR MEANS, SWITCH MEANS OPERATIVELY COUPLED TO THE FILTER MEANS IN THE FIRST STATE OF OPERATION OF THE SWITCH MEANS TO PASS THE FIRST REFERENCE SIGNAL WHEN THE FILTER MEANS PASSES THE FIRST REFERENCE SIGNAL AND OPERATIVELY COUPLED TO THE SECOND MEANS IN THE SECOND STATE OF OPERATION OF THE SWITCH MEANS TO PASS THE SECOND REFERENCE SIGNAL PRODUCED BY THE SECOND MEANS WHEN THE FILTER MEANS BLOCKS THE FIRST REFERENCE SIGNAL, AND THIRD MEANS OPERATIVELY COUPLED TO THE SWITCH MEANS FOR DETECTING THE REFERENCE SIGNAL PASSED BY THE SWITCH MEANS.