Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
A method of generating a unique index mark from the commutation signal of a d.c. brushless motor characterised by, sensing the commutation signal from the motor, dividing the frequency of the commutation signal to provide at least two index signals per revolution, providing at least one track on the disk surface on which magnetic signals synchronised to one of the index signals are stored, said synchronising signals being stored on a proportion of said at least one track, the other proportion of said at least one track being erased, said proportions being determined by the number of phases of the motor, and sensing the synchronising signals on said at least one track and correlating the synchronising signals with one index signal to provide a unique index mark, the correlation providing the same unique index mark every revolution of the motor.
Claim 2
Independent Claim
140 words
A method of generating a unique index mark from the commutation signal of a d.c. brushless motor characterised by, sensing the commutation signal from the motor, dividing the frequency of the commutation signal to provide at least two index signals per revolution, providing at least one track on the disk surface on which magnetic signals synchronised to one of the index signals are stored, said synchronising signals being stored on a proportion of said at least one track, the other proportion of said at least one track being erased, said proportions being determined by the number of phases of the motor, and sensing the synchronising signals on said at least one track and correlating the synchronising signals with one index signal to provide a unique index mark, the correlation providing the same unique index mark every revolution of the motor.
Claim 3
Dependent Claim
135 words
Apparatus for generating a unique index mark from the commutation signal of a d.c. brushless motor characterised in that at least one track on the disk surface in which magnetic signals are stored, said magnetic signals being stored on a proportion of said track, the other proportion of the track being erased, said proportions being determined by the number of phases of the motor, means for sensing the magnetic signals on said track, means for sensing the commutation signal from the brushless d.c. motor, processing means connected to said sensing means for processing said commutation signal to give two identical index signals, means for synchronising said magnetic signal on said track with one of said index signals whereby a unique index mark is produced, said synchronising means providing the same unique index mark every revolution.
Claim 4
Dependent Claim
135 words
Apparatus for generating a unique index mark from the commutation signal of a d.c. brushless motor characterised in that at least one track on the disk surface in which magnetic signals are stored, said magnetic signals being stored on a proportion of said track, the other proportion of the track being erased, said proportions being determined by the number of phases of the motor, means for sensing the magnetic signals on said track, means for sensing the commutation signal from the brushless d.c. motor, processing means connected to said sensing means for processing said commutation signal to give two identical index signals, means for synchronising said magnetic signal on said track with one of said index signals whereby a unique index mark is produced, said synchronising means providing the same unique index mark every revolution.
Claim 5
Dependent Claim
24 words
Apparatus as claimed in claim 2 characterised in that said means for sensing the data on said data track is a magnetic read/write head.
Claim 6
Dependent Claim
34 words
Apparatus as claimed in claim 2 or claim 3 characterised in that said means for synchronising is a microprocessor and is combined with said processing means which is a multivibrator, in a single unit.