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公开(公告)号：DE68923269T2
公开(公告)日：1996-02-08
申请号：DE68923269
申请日：1989-04-26
Applicant: IBM
Inventor： WALLIS CHRISTOPHER NORMAN
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公开(公告)号：GB1126160A
公开(公告)日：1968-09-05
申请号：GB3936967
申请日：1967-08-26
Applicant: IBM
Inventor： OWEN CHARLES EDWARD , WALLIS CHRISTOPHER NORMAN
Abstract: 1,126,160. Data storage. INTERNATIONAL BUSINESS MACHINES CORP. 26 Aug., 1967, No. 39369/67. Heading G4C. [Also in Division H3] A circuit for selecting regularly recurring pulses e.g. from a magnetic disc store comprises a gate and a ramp generator, the pulses providing one input to the gate and the other input being provided by the ramp when it exceeds a controlled value, the flyback of the ramp having a constant amplitude irrespective of ramp length and being initiated by the output of the gate. As applied to a magnetic disc store, binary data D (Fig. 2a) is represented by the presence and absence of a pulse between succesive clock pulses C. The data pulses cause the recorded clock pulses to be pushed apart, as shown dotted, but as the flyback is of constant amplitude the point at which the ramp (Fig. 2b) crosses the threshold T of the gating circuit is not affected. The input pulse train 2(a) alternatively may be derived (Figs. 3a-3g, not shown) from a signal (Fig. 3a) in which a change of binary data between its two values is represented by a change of phase of the signal. The signal is differentiated (3c) squared (3d) and produces pulses at the resulting leading and trailing edges (3c and f). These are combined to form the derived train (3g). Circuit details (Fig. 1).-The input pulses (2a) are applied at 13 to gate 14. The output pulses of the gate discharge capacitor 18 through diode 19 and the trailing edge transfers the charge to a Miller capacitor 21 to produce a determined magnitude of flyback. Capacitor 21 then discharges linearly to produce a ramp voltage (2b) at the input of transistor 32. The input of this transistor comprises a circuit which biases it to allow a predetermined portion of the end of the ramp to pass through transistors 32 and 37 to produce pulses 2(c) which are applied to the other input of gate 14 and thus to allow the next clock pulse to pass. The output from 32 is also applied to a gate 15 to block the clock pulses and allow the data to pass. An averaging circuit 26 1 , 27 controls the rate of discharging of the Miller capacitor 21 so as to stabilize the amplitude of the sawtooth wave.
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公开(公告)号：DE2753589A1
公开(公告)日：1978-06-22
申请号：DE2753589
申请日：1977-12-01
Applicant: IBM
Inventor： WALLIS CHRISTOPHER NORMAN
Abstract: An actuator comprising a transformer having a fixed primary winding on a magnetic core and a pivotally movable coil linked with the magnetic core and forming a secondary winding of the transformer. A permanent magnet generates a static magnetic field in which the coil is disposed. A transducer arm capable of pivotal movement is attached to the coil. When a current pulse is applied to the primary winding, a current is induced in the coil which reacts with the static magnetic field to cause pivotal movement of the coil and attached arm.
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公开(公告)号：DE68919211D1
公开(公告)日：1994-12-08
申请号：DE68919211
申请日：1989-03-29
Applicant: IBM
Inventor： LEE ADRIAN CHARLES FREDERICK , WALLIS CHRISTOPHER NORMAN , MURFET PHILIP JOHN , FURNISS STEPHEN , WINLOW THOMAS , PALMER MICHAEL JOHN
Abstract: An asynchronous serial data receiver for receiving a stream of data bits, characterised by a plurality of shift registers (54) into which samples corresponding to points within said data bit stream are read, different shift registers (54) holding a different set of said samples, said points being separated by most one half of a data bit period, and a decoder (60-90) responsive to said samples held in said shift registers (54) for recognising points of known phase within said data assessed relative to which samples which corresponding to points within said data bits may be identified for reading. The invention provides a high speed serial receiver which is particularly suitable for use within disc drives and data storage and retrieval systems in general. The serial data receiver of the present invention does not require a clock synchronised with the incoming data. Furthermore the serial data receiver is able to share the sampling of the data bit stream between a plurality of shift registers (54) none of which need be clock more than once per data bit period.
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公开(公告)号：FI761760A
公开(公告)日：1976-12-21
申请号：FI761760
申请日：1976-06-17
Applicant: IBM
Inventor： RIGBEY LEONARD JOHN , WALLIS CHRISTOPHER NORMAN
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Patent Agency Ranking
公开(公告)号：DE68919211T2
公开(公告)日：1995-05-11
申请号：DE68919211
申请日：1989-03-29
Applicant: IBM
Inventor： LEE ADRIAN CHARLES FREDERICK , WALLIS CHRISTOPHER NORMAN , MURFET PHILIP JOHN , FURNISS STEPHEN , WINLOW THOMAS , PALMER MICHAEL JOHN
Abstract: An asynchronous serial data receiver for receiving a stream of data bits, characterised by a plurality of shift registers (54) into which samples corresponding to points within said data bit stream are read, different shift registers (54) holding a different set of said samples, said points being separated by most one half of a data bit period, and a decoder (60-90) responsive to said samples held in said shift registers (54) for recognising points of known phase within said data assessed relative to which samples which corresponding to points within said data bits may be identified for reading. The invention provides a high speed serial receiver which is particularly suitable for use within disc drives and data storage and retrieval systems in general. The serial data receiver of the present invention does not require a clock synchronised with the incoming data. Furthermore the serial data receiver is able to share the sampling of the data bit stream between a plurality of shift registers (54) none of which need be clock more than once per data bit period.
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公开(公告)号：DE3374731D1
公开(公告)日：1988-01-07
申请号：DE3374731
申请日：1983-06-30
Applicant: IBM
Inventor： WALLIS CHRISTOPHER NORMAN
Abstract: Functions of the head position error signal from a demodulator (21) and of input (30) to the head position actuator (26) during at least one revoltuion of the disc are combined into an eccentricity-related function. This is stored in a first-in first-out buffer (37) for addition (24) during the next revolution to output from a closed-loop track-following system compensator (23). The eccentricity function may be a track shape position signal obtd. by subtraction (34) of position error signal from the double integral(31) of actuator current; or a current profile obtd. from the difference between the second derivative of position error signal and the actual current.
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公开(公告)号：DE2623572A1
公开(公告)日：1976-12-23
申请号：DE2623572
申请日：1976-05-26
Applicant: IBM
Inventor： RIGBEY LEONARD JOHN , WALLIS CHRISTOPHER NORMAN
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公开(公告)号：GB1135970A
公开(公告)日：1968-12-11
申请号：GB3174667
申请日：1967-07-11
Applicant: IBM
Inventor： WALLIS CHRISTOPHER NORMAN
Abstract: 1,135,970. Electric motors. INTERNATIONAL BUSINESS MACHINES CORP. 11 July, 1967 [31 March, 1967], No. 31746/67. Heading H2A. In the stepping motor control system shown in Fig. 3 of Specification 1,068,972, hunting of the rotor when it reaches the desired position is reduced by connecting a series resonant circuit including a capacitor across at least one of the pole windings of the motor. The motor has pole windings I, II, III, IV which are sequentially energized in pairs according to the energization state of photo-sensitive elements P3, P4 which are illuminated through slots in a mask mounted on the rotor shaft. In operation when the desired position is reached, circuitry 200 sets bi-stable flip-flop 106 to provide an output on line 137. This output enables gates 140, 142 to energize two of the windings and provide a locating torque on the rotor. Each pole winding has a series circuit comprising capacitor (201-4) and reed switch contacts (205-8) connected across it, the switches being closed by energization of coils (209-212) by the signal on line 137. When the switches are closed the capacitor and winding provide a resonant circuit which may be turned to provide optimum damping. In a modification, Figure 2 (not shown), the coils are supplied through gates which are enabled by the signal on line 137 and the current flowing in a non-associated pole winding, so that the switches are only closed for windings which are not energized.
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公开(公告)号：DE68923269D1
公开(公告)日：1995-08-03
申请号：DE68923269
申请日：1989-04-26
Applicant: IBM
Inventor： WALLIS CHRISTOPHER NORMAN
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