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公开(公告)号：AU1401676A
公开(公告)日：1977-12-01
申请号：AU1401676
申请日：1976-05-17
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , TAYLOR JOHN RICHARD
Abstract: A positioning system for data storage apparatus in which a magnetic transducer is positioned relative to data tracks on a moving record member by means of a closed loop servo system. Improved velocity control information is provided to the servo system by pre-recorded servo tracks read by a single servo head forming part of the closed loop system. Each servo track consists of a plurality of servo cells, alternate ones of which are laterally displaced by half a track width. A position reference signal is prerecorded in each cell at a point which is predetermined to permit the signal to be sensed by the single servo head independently of any other detectable signal. Accordingly, a position error signal derived from displaced cells is always 90 DEG out of phase with the position error signal derived from undisplaced cells. During a track access operation, when the servo head is moved from one track to another track, the displaced and undisplaced cells are sensed by the single servo head to provide two separate position error signals. Control circuits combine selected portions of the two position error signals to provide a composite signal of improved linearity from which the velocity of the head during the access operation can be ascertained directly and employed to perform control functions dependent on velocity.
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公开(公告)号：GB1193804A
公开(公告)日：1970-06-03
申请号：GB611569
申请日：1969-02-05
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN
IPC: G11B15/087 , G11B20/12 , G11B20/14 , G11B27/10
Abstract: 1,193,804. Pulse discriminating circuits. INTERNATIONAL BUSINESS MACHINES CORP. 5 Feb., 1969, No. 6115/69. Heading H3T. [Also in Division G4] A pulse selecting circuit comprises an input gate receiving the input pulse train, a sawtooth generator having a fixed amplitude flyback and which opens the gate when the ramp exceeds a given level, the generator being triggered by the output from the gate, a further gate receiving the output of the first and being enabled by the ramp generator when the flyback does not pass a given threshold level due to the spacing between the triggering pulses and thus the amplitude of the ramp exceeding a given value. The invention is applied to a train of pulses from a magnetic storage disc, data being represented by pulses D1, Fig. 4a preceded by a clock pulse C and the address by pulses 54, 55 not preceded by a clock pulse. The input circuit comprises a combination of gate 14 and a flyback and ramp generator having a fixed amplitude flyback, described in Specification 1,126,160 and with reference to Fig. 2 (not shown). Briefly, the ramp generator produces an output 4b which, following a clock pulse, provides a gating pulse 4c lasting until the ramp reaches a valve L, the pulse closing gate 14 long enough to block the next data pulse so that only clock pulses and address pulses (i.e. pulses not preceded by a clock pulse) are selected by gate 14, the output of the gate being used to trigger the flyback. The circuit also selects at 15 (Fig. 2) the data pulses. The gating pulses 4c and the selected clock and address pulses from 14 are applied to an AND gate 59 to produce pulses 4d coincident with clock and address pulses. Gates 60 and 63 are crosscoupled to form a bi-stable circuit. It is set by pulses from 14 and reset when the flyback passes threshold L, to produce pulses 4(e). Thus it remains reset during the absence of clock pulses. Gates 68 and 70 also form a bistable circuit. It is controlled by 4e and by the output of an AND gate 66 itself controlled by 4e and the output of gate 14 so as to produce narrow pulses concident with clock pulses and pulses starting at the second address pulse and ending at the next clock pulse 4h. These pulses control a gate 72 which also receives the output of a gate 14 so as to produce pulses coincident with the second address pulse and the next clock pulse (4k). In order to prevent zero drift and pulse timing errors, shown dotted in 4(b), from causing false switching of bi-stable circuit 60, 63, a monostable circuit 74 produces inhibit pulses during this period. The second bi-stable circuit may be replaced by a timing circuit.
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公开(公告)号：DE3472867D1
公开(公告)日：1988-08-25
申请号：DE3472867
申请日：1984-02-29
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , FENTON BRIAN PETER , RAMAGE JOHN GILBERT
IPC: H02M7/537 , H02M7/5387 , H03K17/691 , H02M1/08 , H02M3/335 , H02P1/18 , H02P6/02
Abstract: The power switching circuit employs a solid state device (14) responding to a drive signal at its output to switch power repetitively to a load at a low frequency. The device is driven across an isolating transformer interface (60). The drive signals are HF pulse signals which are modulated withthe LF switching information. The modulations are detected in the secondary winding (62) of the transformer. Power for the detector is derived by a diode bridge (120-123) rectifying the HF signals induced in the transformer secondary output. The current through the device is sensed and chopped to keep it within safety limits.
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公开(公告)号：CH609797A5
公开(公告)日：1979-03-15
申请号：CH604476
申请日：1976-05-14
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , TAYLOR JOHN RICHARD
Abstract: A positioning system for data storage apparatus in which a magnetic transducer is positioned relative to data tracks on a moving record member by means of a closed loop servo system. Improved velocity control information is provided to the servo system by pre-recorded servo tracks read by a single servo head forming part of the closed loop system. Each servo track consists of a plurality of servo cells, alternate ones of which are laterally displaced by half a track width. A position reference signal is prerecorded in each cell at a point which is predetermined to permit the signal to be sensed by the single servo head independently of any other detectable signal. Accordingly, a position error signal derived from displaced cells is always 90 DEG out of phase with the position error signal derived from undisplaced cells. During a track access operation, when the servo head is moved from one track to another track, the displaced and undisplaced cells are sensed by the single servo head to provide two separate position error signals. Control circuits combine selected portions of the two position error signals to provide a composite signal of improved linearity from which the velocity of the head during the access operation can be ascertained directly and employed to perform control functions dependent on velocity.
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公开(公告)号：BR8500628A
公开(公告)日：1985-10-01
申请号：BR8500628
申请日：1985-02-12
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , FENTON BRIAN PETER , RAMAGE JOHNS GILBERT
IPC: H02M7/537 , H02M7/5387 , H03K17/691 , H02P1/42 , H02P1/30
Abstract: A power switching circuit for switching power repetitively to a load at a relatively low frequency employs a power switching device which is driven across an isolating transformer interface. The drive signals are high frequency pulse signals which are modulated with the low frequency switching information, the modulations being detected in the secondary circuit of the transformer. Such an arrangement affords isolated driving with fast switching edges and requires only a small transformer. Power for the detection circuit is derived by rectification of the high frequency signals induced in the transformer secondary.
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Patent Agency Ranking
公开(公告)号：DE2755652A1
公开(公告)日：1978-06-29
申请号：DE2755652
申请日：1977-12-14
Applicant: IBM
Abstract: A data storage apparatus, such as an accessing head magnetic disk file, includes at least one data disk surface and a servo disk surface. In operation, a continuous position signal having high frequency components is derived from the servo surface, which has a quadature type servo signal prerecorded thereon. A circuit means modifies the derived position signal so that a substantially linear signal representing the displacement of the servo head from the servo track is obtained. A second position signal having a low frequency component is obtained from servo sector information registered on the data disk surface and together with the first position signal forms a hybrid position signal. This hybrid signal is used to control the movement of the data heads relative to the data tracks to ensure optimum transducing operation.
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公开(公告)号：CH600481A5
公开(公告)日：1978-06-15
申请号：CH944576
申请日：1976-07-23
Applicant: IBM
Inventor： CASE WILLIAM JOHN PHILIP , COMMANDER ROBERT DUNCAN
Abstract: Data track positioning information for data tracks on a stack of recording disks is provided by servo information pre-recorded on one surface of the stack. In addition, each data track on the remaining surfaces of the stack has servo information relative to that track pre-recorded in sectors around the track. Track following operations are controlled in a closed loop servo system using on-track position information derived from the sectored servo tracks associated with the track being followed. The bandwidth of the position error signal derived from the sectored servo information is increased by adding high frequency components obtained from the continuous servo information on the servo surface. Track access operations are controlled using track crossing information derived from the pre-recorded servo information on the servo surface.
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公开(公告)号：AU1625576A
公开(公告)日：1978-02-02
申请号：AU1625576
申请日：1976-07-26
Applicant: IBM
Inventor： CASE WILLIAM JOHN PHILIP , COMMANDER ROBERT DUNCAN
Abstract: Data track positioning information for data tracks on a stack of recording disks is provided by servo information pre-recorded on one surface of the stack. In addition, each data track on the remaining surfaces of the stack has servo information relative to that track pre-recorded in sectors around the track. Track following operations are controlled in a closed loop servo system using on-track position information derived from the sectored servo tracks associated with the track being followed. The bandwidth of the position error signal derived from the sectored servo information is increased by adding high frequency components obtained from the continuous servo information on the servo surface. Track access operations are controlled using track crossing information derived from the pre-recorded servo information on the servo surface.
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公开(公告)号：DE2629710A1
公开(公告)日：1977-01-27
申请号：DE2629710
申请日：1976-07-02
Applicant: IBM
Inventor： CASE WILLIAM JOHN PHILIP , COMMANDER ROBERT DUNCAN
Abstract: Data track positioning information for data tracks on a stack of recording disks is provided by servo information pre-recorded on one surface of the stack. In addition, each data track on the remaining surfaces of the stack has servo information relative to that track pre-recorded in sectors around the track. Track following operations are controlled in a closed loop servo system using on-track position information derived from the sectored servo tracks associated with the track being followed. The bandwidth of the position error signal derived from the sectored servo information is increased by adding high frequency components obtained from the continuous servo information on the servo surface. Track access operations are controlled using track crossing information derived from the pre-recorded servo information on the servo surface.
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公开(公告)号：DE2612111A1
公开(公告)日：1976-11-18
申请号：DE2612111
申请日：1976-03-22
Applicant: IBM
Inventor： COMMANDER ROBERT DUNCAN , TAYLOR JOHN RICHARD
Abstract: A positioning system for data storage apparatus in which a magnetic transducer is positioned relative to data tracks on a moving record member by means of a closed loop servo system. Improved velocity control information is provided to the servo system by pre-recorded servo tracks read by a single servo head forming part of the closed loop system. Each servo track consists of a plurality of servo cells, alternate ones of which are laterally displaced by half a track width. A position reference signal is prerecorded in each cell at a point which is predetermined to permit the signal to be sensed by the single servo head independently of any other detectable signal. Accordingly, a position error signal derived from displaced cells is always 90 DEG out of phase with the position error signal derived from undisplaced cells. During a track access operation, when the servo head is moved from one track to another track, the displaced and undisplaced cells are sensed by the single servo head to provide two separate position error signals. Control circuits combine selected portions of the two position error signals to provide a composite signal of improved linearity from which the velocity of the head during the access operation can be ascertained directly and employed to perform control functions dependent on velocity.
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