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Patent Agency Ranking
公开(公告)号：DE1524775A1
公开(公告)日：1970-10-08
申请号：DEJ0033032
申请日：1967-02-18
Applicant: IBM
Inventor： JAMES BLACK ROBERT , JOHN SORDELLO FRANK
Abstract: 1,127,563. Automatic position control. INTERNATIONAL BUSINESS MACHINES CORP. Feb. 17, 1967 [ March 2, 1966], No. 7584/67. Addition to 987, 357. Heading G3R. [Also in Divisions G4 and G5] In a memory system according to the parent Specification in which a magnetic transducer is positioned over a desired data track by a servosystem actuated in response to servo-signals recorded in tracks adjacent the data tracks, the servo-signals in adjacent tracks are of the same frequency but have portions in anti-phase so that when the transducer is positioned over the desired data track no servo error signals are produced. As described, a disc 10 (Fig. 1) has magnetizable layers 11, 12 respectively of high and low coercivity and carrying respectively servo-tracks ST 1 -- Fig. 3 (not shown) and data tracks DT 1 -- spaced between the servo-tracks. The servo-tracks may, however, be arranged above or below the associated data tracks. The servo-signals (Fig. 4) are sinusoidal over most of their length but are reversed in phase at selected points such as 1 1 -1 3 , t 1 and 1 4 , t 2 so as to define periods a 1 , b 1 &c. of duration indicative of particular tracks by which coarse positioning of the transducer is achieved. The main leading and trailing phase reversals 1 2 , 1 4 and t 1 , t 2 are arranged on radial and spiral lines LR 1 - - - and LS 1 --- respectively. Servo-control: The servo-signal picked up by the head 21 (Fig. 1) takes the form of a suppressedcarrier, double-sideband signal which is separated from the data signals by a band pass amplifier 23 and smoothed by a filter 31 so that the resulting servo-signal has positive pulses at the radial lines and negative pulses at the spiral lines. The radial and spiral line pulses are separated at 32, 33 and fed to a coarse position detector 40 (also Fig. 2) to position the head near the addressed track. The positive (radial) pulses actuate an oscillator 46 to start a binary count cycle whose instantaneous value is compared with an address register 41 and a differentially timed pulse generated, when the values are equal, for comparison in phase discriminator 62 with a negative (spiral) pulse, the output of the discriminator controlling the head position actuator 64. A gate 61 is arranged to be opened when the coarse error signal from the detector 40 is minimal so that fine position signals, filtered from the amplifier 23 and demodulated 52, may pass to a summing gate 62 and thence to the actuator 64, control stability being improved by a tachometer. The demodulating carrier is derived from oscillator 46 in the detector 40 and the resulting, demodulated fine error signals are of amplitude and polarity indicative of magnitude and direction of error.
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公开(公告)号：DE1474392A1
公开(公告)日：1969-08-07
申请号：DE1474392
申请日：1965-12-11
Applicant: IBM
Inventor： JAMES BLACK ROBERT , JOHN SORDELLO FRANK
Abstract: 1,073,875. Positioning magnetic head assemblies; electric selective signalling. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 17, 1965 [Dec. 16, 1964], No. 48777/65. Headings G4H and G5R. [Also in Division H3] A magnetic head assembly (22, Fig. 1, not shown) is positioned radially on one of 512 tracks on a magnetic disc (10) by comparing the number of the desired track with the number of the actual track and using the error signal to correct the position. The disc may include a clock track (14) operating on a count base of 512 and feeding a binary counter (44, Fig. 2, not shown). A first digital quantity representing the desired track is stored in a register (40), and a second digital quantity representing the actual track is stored in a second register (42), the two registers feeding respective comparators (46 and 47) which produce output pulses each time the binary counter (44) reaches the corresponding digits. The output pulses are used to start and stop ramp generators which produce an output which is proportional to the magnitude and sense of the error and which is used to control a transducer positioning mechanism. The transducer mechanism may include a reference pattern sensor of magnetic or optical type for indicating the. actual track, or the reference track (14) may include radial variations by which the separate data track positions may be identified. The disc (10) may be one of a number of parallel discs in a multi-disc array mounted on a common shaft.
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公开(公告)号：DE1588357A1
公开(公告)日：1970-09-10
申请号：DE1588357
申请日：1967-12-15
Applicant: IBM
Inventor： JAMES BLACK ROBERT , JOHN SORDELLO FRANK , STEWART SWARTZ JACK
Abstract: 1,145,817. Servo systems. INTERNATIONAL BUSINESS MACHINES CORP. 27 Dec., 1967 [5 Jan., 1967], No. 58604/67. Heading G4H. The system described in Specification 1,073,875 is modified in that the frequency of the oscillator supplying the continuously cycling counter is varied in dependence on the error signal. The error signal is proportional to the square root of the position error and the overall gain of the system is reduced when large errors exist. The frequency of the oscillator may be varied by an external control signal in conjunction with the error signal and a velocity feedback signal may be combined with the error signal.
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公开(公告)号：DE1513215A1
公开(公告)日：1970-01-02
申请号：DE1513215
申请日：1965-12-09
Applicant: IBM
Abstract: 1,070,680. Positioning systems; data storage. INTERNATIONAL BUSINESS MACHINES CORPORATION. Nov. 16, 1965 [Dec. 21, 1964], No. 48531/65. Headings G4C and G4H. Apparatus positioning a movable member relative to a rotatable disc bearing a positiondefining pattern, compares the desired and actual radial positions to generate an error signal, and also generates timing signals indicative of the rotation of the disc. A reference pattern (30) on a magnetic disc store (10) comprises "spokes," each with a radial edge and an edge which is part of an Archimedean spiral. A radially movable transducer assembly (12) bearing the magnetic read-record heads also delivers light to the pattern (30) and routes reflected light to a detector (50). Time base pulses are derived from crossing of the radial edges of the pattern (30) and pulses indicating by their timing the radial position of the transducer assembly (12) are derived from crossing of the spiral edges. The relative phase of the time base pulses and the overflow pulses from a recycling binary counter (72) fed by an oscillator (73) is used to adjust the oscillator frequency so that the relative phase is zero. The counter (72) reading is compared (80) with the required radial position (address) from a computer (16) to produce a pulse train the phase of which is compared (90) with that of the actual-radialposition pulses to produce an amplitude-significant error voltage which controls the transducer (12) position through a velocity feedback position servo (100). As a modification, the store may be a magnetic drum, both edges of the pattern strokes being linear. The optical sensing of the reference pattern could be replaced by magnetic or radiation sensing.
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公开(公告)号：DE1915548A1
公开(公告)日：1969-10-02
申请号：DE1915548
申请日：1969-03-27
Applicant: IBM
Inventor： RONALD BEACH JUN LAURENCE , HENRY KALTHOFF CLEMENT , BOULDER COL , JAMES BLACK ROBERT
IPC: G11B5/54 , G11B5/55 , H02K41/035 , H02K41/02
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