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公开(公告)号：EP0108060A4
公开(公告)日：1985-11-07
申请号：EP82902023
申请日：1982-05-17
Applicant: IBM
Inventor： AXMEAR FREDERICK EUGENE , BAXTER DUANE WILLARD , SAXMAN JOHN HUMPHREY , SIVERLING MICHAEL MCHUGH
CPC classification number: G11B5/5547 , G11B21/083
Abstract: A sector servo seek control samples each sector to obtain sector time, the track identification within a sequence of track types and a position error signal for a track location to track location seek. The device during each sector determines the actual transducer track location and the next sector projected track location with respect to the sequence of track types. The projected track location is corrected using the error signal to find the actual location, but if a sector signal is missing or erroneous, the projected location is used as the actual location, permitting a composite correction to be made when a correct sector signal is obtained. The seek time is minimized by using maximum acceleration followed by maximum deceleration while not exceeding a velocity value that would cause the device to overshoot the target track using full deceleration.
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公开(公告)号：DE3280376D1
公开(公告)日：1992-01-02
申请号：DE3280376
申请日：1982-05-17
Applicant: IBM
Inventor： AXMEAR FREDERICK EUGENE , BAXTER DUANE WILLARD , SAXMAN JOHN HUMPHREY , SIVERLING MICHAEL MCHUGH
Abstract: An analog position error signal is digitised and latched. If a signal occurs on missing sector line, the output of selection circuit goes to five zero bits and error correction is prevented. The lost sector projected position, latched during the previous cycle register is truncated and rounded to an integer indicating the track type by a circuit. The select circuit also responds to the missing sector signal to select the last sector projected position from the bus. The selection circuit outputs are summed and an actual position signal is put on a bus. A circuit subtracts the last position stored from the bus position, to derive a valve representing velocity in the sector, which is latched. The velocity is then used to compute a projected location which is put onto a bus and loaded into the output register of the projected track psotion circuit. In this way, on error condition can be allowd for several sector times before the condition is reached where the next sector signal can not restore the correct actual position.
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Patent Agency Ranking
公开(公告)号：DE3277259D1
公开(公告)日：1987-10-15
申请号：DE3277259
申请日：1982-05-12
Applicant: IBM
Inventor： SIVERLING MICHAEL MCHUGH
Abstract: The servo system includes the use of servo signals of four types such that each group of four adjoining servo tracks identifies the center line of a data track of interest and presents unique signals from the respective four servo tracks. The analog value of the signals are stored and sensed to provide a substantially linear position error signal over a three-track wide region. By using variable gain with respect to the analog signals, compensation for the variance between data head width and track pitch, and a quadrature servo portion, linearity can be achieved. In addition, since the substantially linear region is three tracks wide and the position error signal does not become ambiguous over a width of four tracks, a one-track seek can be accomplished using an error signal rather than a seek.
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公开(公告)号：DE3066248D1
公开(公告)日：1984-03-01
申请号：DE3066248
申请日：1980-05-09
Applicant: IBM
Inventor： SIVERLING MICHAEL MCHUGH , WHEELER STEPHEN EDWARD
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公开(公告)号：DE2846624A1
公开(公告)日：1979-05-31
申请号：DE2846624
申请日：1978-10-26
Applicant: IBM
Abstract: Analog voltage levels derived from optically scanning a document or from magnetically scanning a magnetic record, depend upon the variable amplitude of a background signal. The analog voltage levels are processed by a bucket brigade circuit to set a threshold from which a binary decision may be made as to the presence of a black or white indicium in optical recognition or a one (1) or zero (0) bit in magnetic reading.
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公开(公告)号：DE2823679A1
公开(公告)日：1979-02-01
申请号：DE2823679
申请日：1978-05-31
Applicant: IBM
Abstract: An array of optically sensitive devices senses printed matter with each device in the array producing an output signal representing a single black or white element in a multi-element picture being sensed by the whole array. These output signals are fed into an analog charge transfer shift register and passed serially in a fixed sequence through an output stage of the shift register. As the signal from each device passes through this output stage the device becomes what is hereafter referred to as the device of interest and the signal produced by it is analyzed to determine whether it is a black or white element. Other output stages simultaneously sense data from devices located around the device of interest to define a subarray within the original detected array while the last of these output stages is fed to a peak comparator to sense the brightest and darkest matter detected in the recent past by any element of the array. The results of these sensings are processed in accordance with a preselected algorithm to generate a digital signal wich is an indication of whether the device of interest has detected black or white.
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公开(公告)号：DE2262855A1
公开(公告)日：1973-07-12
申请号：DE2262855
申请日：1972-12-22
Applicant: IBM
Inventor： BJERKE BRIAN KENNETH , SIVERLING MICHAEL MCHUGH
Abstract: An illumination provides incident radiation to a document lying in an object plane. A photodetector converts nonspecular reflections from the plane into an electrical signal. To prevent unwanted specular reflections, from plastic mail-piece windows or uneven documents, for degrading the signal-to-noise ratio, an optical diffuser is located adjacent the object plane. Both the incident and the reflected radiation pass through the diffuser, which may be a ground-glass flat.
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