Abstract: An apparatus and method are disclosed for processing syndrome bytes in a multibyte error correcting system in which up to t errors are correctable by processing 2t syndrome bytes. The method involves converting syndrome bytes into t+1 coefficients of the error locator polynomial by predetermined product operations and exclusive-OR operations involving selected syndrome bytes to produce cofactors that correspond to the desired coefficients when less than t errors occurred in the codeword. The cofactors are combined to produce coefficients when t errors occur and the correct set of coefficients are selected in accordance with the number of errors that are detected.The apparatus involves logical circuitry for obtaining sets of coefficients from selected syndrome bytes where each set is associated with a different number of errors in the codeword and in which a set of coefficients associated with t-1 errors is a cofactor of the set of coefficients associated with t errors.

Abstract: In a magnetic recording disk file employing a transducing slider which is closely spaced from the disk surface and has side rail members extending in the direction of disk motion and tapered portions at the leading edge, the disk may be cleaned of contaminant particles by moving the slider in increments from the outside disk diameter to the inside diameter, so that the particles first encounter the slider/inner side rail and are swept away, rather than first encountering the tapered portions and being wedged into the magnetic coating.

Abstract: In spin coating a liquid magnetic dispersion onto a rotating annular substrate, a stationary fluid barrier member is positioned closely adjacent the substrate after deposition of the dispersion thereon and during the time the excess dispersion is spun off, the substrate has a radial opening therein which permits fluid communication between the outer portion of the fluid barrier and its inner portion. The barrier member serves to reduce the rate of solvent evaporation from the dispersion so that the dispersion flows more readily during spin-off to produce a thinner resulting magnetic coating.

Abstract: In a magnetic disk file, the longitudinal rails of an air-bearing head slider are skewed at a predetermined angle relative to a tangential velocity vector line that passes through a transducer tangent to the particular data track over which said transducer is then disposed for causing airborne debris particles that are drawn in under the rails to be directed in a path that substantially avoids said transducer to reduce wear thereof. This angle is sufficient to cause said debris particles to be dispersed into a viscous fluid stream that flows outboard of said tangential velocity vector line and said transducer.

Abstract: An ultrasonic probe (1) for use with ultrasonic imaging apparatus for investigating the internal structure of a body contains a pair of pulse echo receivers (RA1, RB1; RA2, RB2; . . . ) for each pulse transmitter in a linear array of transmitters (T1, T2, . . . ). The two receivers (A,B) in each pair lie in a plane at right-angles to the pulse propagation axis of the associated transmitter and equidistant therefrom. The outputs from the two receivers in each pair are correlated by multiplying in multipliers (11.1, 11.2, 11.3) so that in use the time coincident components of the two waveforms in each receiver pair are emphasized, thus focussing the echo information in the longitudinal plane of symmetry (4) of the probe.

Abstract: The gripping apparatus described comprises a four-bar linkage arrangement for so controlling movement of the two pairs of parallel beams and fingers operatively connected thereto as to cause the gripping surfaces of the fingers to concurrently move in rectilinearly aligned paths and remain parallel throughout their excursion during gripping and releasing of an article and apply a constant gripping force to the article irrespective of the extent to which the fingers are moved toward each other into gripping contact. The beams are pivotally connected directly at their one ends, and also intermediate their ends via links, to a fixed member; and the beams at their opposite ends have a pin-in-slot connection with the fixed member. When force is applied to the links to operatively cause the fingers to grip the article, the links will rock and the arc described by each beam will be accurately cancelled by the arc generated by each link.

Abstract: An optical fluid analyzing apparatus is shown comprising transparent means (12,13) of known refractive index (n.sub.1) providing a cell (14) for receiving a fluid sample of unknown refractive index (n.sub.2). A diffraction grating 10 is formed in an inner wall (11) of the cell. A light source (15) is positioned at an incident angle (.theta..sub.0) with a grating to satisfy the Bragg condition. A pair of detectors (16, 17) intercept the 0th order and 1st order diffracted light. Circuitry (18) responds to signals generated by the detectors to provide an output indicative of the refractive index of the sample.

Abstract: A process is described for fabricating an encapsulated circuit board. The process involves use of an adhesive which is photochemically curable to a limited preselected depth so as to rigidly fix the circuit wires in X and Y directions while permitting limited pliability of the adhesive and hence mobility of the wires in the Z direction. The adhesive preferably is one which is also thermally curable so that at a later stage of fabrication (e.g., either as a part of or after lamination of individual circuit boards into a multilayered circuit board), the complete unit may be thermally bulk cured to rigidly fix all wires in the Z direction.

Abstract: A flat panel display device comprising a matrix of X and Y drive lines and a plurality of selecting field effect transistors (FETs) is described. Each FET is selectively operable by applying a potential across a unique pair of X and Y drive lines for controlling activation of a corresponding optical transducer. A high value resistance is interposed in series between the gate electrode of each selecting FET and associated drive line to minimize the effect a short circuit caused by a defective gate electrode establishing an electrical connection between X and Y drive lines. The resistance is preferably provided by a segment of undoped polysilicon on a polysilicon circuit line connecting each gate electrode with the associated X drive line.

Abstract: A thin film inductive transducer is shown comprising three magnetic layers (10, 11, 12) deposited on a slider substrate (13) for perpendicular recording of magnetic transitions on a movable magnetic medium. Two magnetic closures are provided. One is defined by electrical contact of one outer magnetic layer (12 or 10) with the intermediate magnetic layer (11 or 11') within the area bounded by conductive turns (a-h) of single layer coil (19 or 19'). The other is defined by electrical contact (10, 12 or 10', 12') outboard of the conductive turns (a-h). Magnetic transitions may be read by conventional peak detection techniques because the disclosed transducer has three pole tips (P1, P2, P3), the central one P2 of which is approximately 33-40% of the thickness of the outer pole tips (P1, P3). To avoid "wrap-around", the pole tips (P1, P2, P3) are progressively narrower in width as their distance from the substrate (13) increases.

Abstract: The apparatus and method herein disclosed is to permit modular mounting and packaging of a plurality of data processing devices of different configurations and functions in a standardized wall-like reticulated structure.This structure (10) has front and rear panels (12, 14) containing a plurality of identically configured apertures (11, 13). Covers (22, 23) configured to suit the different functions of the respective devices (17, 18) enclose protruding portions of such devices; but all such covers have identical peripheral dimensions conforming to but somewhat larger than that of the identically configured apertures so that any of the different devices may be mounted in any one of the apertures in the structure. The structures may be arranged in in line or staggered relation or at right angles to form a variety of configurations, but each structure is preferably connected to a respective support panel to provide a T-shaped free standing entity of high stability.

Abstract: An electric rotary actuator for producing rotation through a limited angle comprises a rotor winding made of a plurality of thin loop coils arranged in a continuous cylindrical framework as part of a rotor shell. The rotor shell lies in an annular flux gap defined by a stator magnet assembly and a flux return means. Each pair of adjacent axially extending limbs of adjacent loop coils lies opposite to and cooperates with a respective stator pole face. This winding arrangement helps to optimize the torsional resonance characteristics of the rotating mass.

Abstract: A multielement magnetic head is formed with a closure section having a nonmagnetic ceramic substrate on which a thin layer of magnetic ferrite is deposited and processed. The thin ferrite layer is cut to define the separate transducing elements and data track separation. The closure section is joined to a wafer formed from a ferrite substrate and a thin film conductive coil means.

Abstract: A single track magnetic head assembly comprises a nonmagnetic base, a magnetic layer disposed on one surface of said base, a nonmagnetic top closure positioned adjacent to an upper portion of said magnetic layer, and a magnetic bridge section positioned adjacent to the lower portion of said magnetic layer and below said top closure. A prewound coil is attached to the bridge section. The base, the magnetic layer and the top closure have arched sections to allow accurate definition of the throat height, and to enable testing of magnetic and physical properties of the magnetic head during the assembly process.

Abstract: A method and apparatus for cleaning residual toner from the surface of an imaging member in an electrographic imaging system which uses carrier means to transport toner by triboelectric forces to develop an electrostatic image on the imaging member. The pre-clean corona current is adjusted periodically during the lifetime of the carrier as necessary substantially to neutralize the charge on residual toner so that it may readily be removed by a rotating cleaning brush having substantially no charge thereon. Adjustment is in response to a periodically sensed aging characteristic, the charge density of the toner, such as at successive preselected operating time intervals representing increments of carrier useful lifetime. In this manner, cleaning efficiency is maintained.

Abstract: A batch fabricated multi-element head is made from interlocking ferrite parts to form a low contoured surface for interfacing with a magnetic medium, such as a flexible disk. On another surface, a multi-turn conductive coil is formed by thin film process and cooperates with a flux path bar to define the magnetic flux field.

Abstract: Aluminum-based alloy films and metallization layers that are patterned by reactive ion etching (RIE) are passivated by etching surface portions of the films or layers with a phosphoric-chromic mixture to remove contaminants and then oxidizing the exposed surface portions in an oxygen atmosphere.

Abstract: A method of manufacturing a novel ferrite magnetic head assembly utilizes two ferrite pieces having extending fingers of closely similar dimensions that are joined in interleaving fashion and bonded to a ceramic substrate. The resultant assembly is sliced to provide closure sections for multi-track magnetic heads. Each closure section is joined to a ferrite wafer such that the wafer and closure section define a transducing gap therebetween.

Abstract: The object of this invention is to purge any entrapped air from the ink cavity (17) and nozzle orifice (15) of the print head (10) of a drop-on-demand ink jet printer. Purging is accomplished automatically as a part of the start up operation and also if, during operation, the velocity V.sub.s of the ink droplets (26), as sensed by a sensor (41), drops below a preselected reference value V.sub.r.The print head comprises a tubular piezoelectric transducer (11). The transducer is energized with a series of pulses for a preselected short time period and at a repetition rate substantially equal to a resonant frequency of the ink cavity. This effectively purges any entrapped air from the ink system. Except during purging, the transducer operates asynchronously in drop-on-demand mode in response to discrete binary print signals.

Abstract: In an apparatus and method for record reorientation following error detection in a data storage subsystem each data track is subdivided into equal time-length recording cells which are sequentially numbered past an index point with the beginning of each field of each record coinciding with an initial cell for the field. Upon detection of a retriable error within a given field, the initial cell for the field is determined and stored, the subsystem is disconnected from an interfacing channel, and reorientation is attempted by advancing a transducer addressing the track past the index point to a location which is a selected distance upstream of the stored cell number. If a selected channel command is then received within a given time interval, the subsystem is reconnected to the channel and reorientation is effected as the transducer enters the field the initial cell of which was stored.