Magnetic recording and reproduction

Claim 1

IN A RECORDING AND REPRODUCING DEVICE INCLUDING A MOTOR FOR DRIVING A TAPE AND A MAGNETIC TRANSDUCER, A SYSTEM FOR SYNCHRONIZING TELEVISION SIGNALS COMPRISING A REFERENCE SYNCHRONIZATION SIGNAL SOURCE, A FIRST PHASE DIFFERENCE DETECTOR COUPLED TO RECEIVE A SIGNAL FROM SAID REFERENCE SIGNAL SOURCE, A MAGNETIC HEAD MECHANICALLY COUPLED TO THE MOTOR FOR DERIVING A REPRODUCED SIGNAL FROM THE TAPE, AN AMPLIFIER TO AMPLIFY SAID REPRODUCED SIGNAL, MEANS FOR FEEDING THE REPRODUCED SIGNAL FROM THE OUTPUT OF SAID AMPLIFIER TO SAID FIRST PHASE DIFFERENCE DETECTOR WHERE THE PHASE OF SAID REPRODUCED SIGNAL IS COMPARED TO THE PHASE OF SAID SIGNAL FROM SAID REFERENCE SOURCE TO DERIVE AN OUTPUT SIGNAL WHICH IS PROPORTIONAL TO A PHASE DIFFERENCE BETWEEN THESE TWO SIGNALS, A SYNCHRONOUS SIGNAL SEPARATOR CIRCUIT COUPLED THROUGH A SIGNAL PATH TO RECEIVE THE SIGNAL FROM SAID REFERENCE SOURCE, SAID SYNCHRONOUS SIGNAL SEPARATOR CIRCUIT FURTHER INCLUDING A VARIABLE DELAY LINE PORTION FOR RECEIVING SAID OUTPUT SIGNAL FROM SAID FIRST PHASE DIFFERENCE DETECTOR, A SECOND PHASE DIFFERENCE DETECTOR COUPLED TO RECEIVE THE OUTPUT FROM SAID SYNCHRONOUS SIGNAL SEPARATOR CIRCUIT, A MOTOR SPEED DETECTOR CIRCUIT AND MEANS FOR FEEDING A SIGNAL THEREFROM TO SAID SECOND PHASE DIFFERENCE DETECTOR WHEREIN AN OUTPUT SIGNAL IS DEVELOPED WHICH HAS A VALUE DEPENDING UPON THE PHASE DIFFERENCE BETWEEN THE SIGNAL FROM SAID MOTOR SPEED DETECTOR CIRCUIT AND THE OUTPUT FROM SAID SYNCHRONOUS SIGNAL SEPARATOR CIRCUIT, A VARIABLE FREQUENCY OSCILLATOR FOR RECEIVING THE OUTPUT SIGNAL FROM SAID SECOND PHASE DIFFERENCE DETECTOR TO VARY THE FREQUENCY THEREOF IN ACCORDANCE WITH VARIATIONS IN THE OUTPUT SIGNAL OF SAID SECOND PHASE DIFFERENCE DETECTOR, AND MEANS FOR COUPLING THE OUTPUT OF SAID OSCILLATOR TO SAID MOTOR TO VARY THE SPEED THEREOF, WHEREBY THE ROTATIONAL FREQUENCY OF SAID MAGNETIC HEAD MAY BE VARIED.