Abstract: A method and apparatus for marring the surface of a fiber optic substrate by feeding the substrate between a pair of rotating rollers. One of the rollers is coated with an abrasive. The second roller may be hard or have a deformable cover. Alternatively, one or both rollers may be serrated to produce a ripple pattern in the substrate. A hydraulic, pneumatic or other device is used for either manually and/or automatically adjusting the gap between the rollers. One or both rollers may also be heated to further enhance the marring action. A cam mechanism may also be used to adjust the pressure in the nip.

Abstract: A track following positioning system including filtered average servo demodulators for maintaining the position of a magnetic tape head in alignment with tracks of data stored in magnetic medium. A servo head tracks a centerline in a servo written region of the magnetic medium and generates servo head signals corresponding to the displacement of the servo head from the centerline. A filtered average servo demodulator detects the servo head signals and generates servo error signals for realigning the tape head with respect to the magnetic medium in response thereto. To generate servo error signals, the filtered average servo demodulator peak detects and averages the rectified and filtered output signals and then subtracts a proportion of the peak detected signals from the average detected signals.

Abstract: A magnetic recording head positioning system includes a Terfenol-D magnetostrictive rod prestressed by a lever arm to operate in a linear range to microposition the magnetic recording head in accordance with an electromagnetic field. The mechanical advantage of the lever arm amplifies changes in the magnetostrictive rod to position the head. The varying electromagnetic field is applied to the rod by a coil in response to a position error signal produced from servo data tracks on the magnetic tape. A permanent magnet system biases the magnetostrictive element with a DC field so that varying the field provides bi-directional motion of the magnetic recording head. The DC field also reduces coil current and size requirements.

Abstract: In a magnetic storage system, an error recovery is performed by reading the magnetic medium again with the filter programmed to a higher boost. If the retry still fails, the magnetic medium is read again with the filter programmed to a lower boost. The filter adjustment can be performed in combination with position adjustment of the read head, i.e. displacing the read/write head from the centerline of the track during error recovery to reduce read errors.

Abstract: A precise motion transducer is described. The transducer converts relatively large inputs, either forces or motions, into relatively small predictable and repeatable motions at the output. The input forces or motions may be produced by a Micrometer, a set of calibrated masses (weights), an electromagnetic voice coil (solenoid) or any other standard or customized device that can produce a calibrated force or motion and deliver this force or motion to the transducer. The force or motion, once delivered to the transducer body, is then transformed into a small motion which is then available to control the position or motion of a component, device or instrument.

Abstract: An oscillating erase current circuit for erasing information recorded on magnetic media. The inductance of an erase head is coupled with capacitors to form a tank circuit having a natural resonant frequency. The self-oscillating erase current circuit generates an oscillating signal having a frequency of oscillation determined by and therefore equal to the natural resonant frequency of the tank circuit. Once enabled, the self-oscillating erase current circuit continuously oscillates without any external drive circuit.

Abstract: A control system having proportional and integral functions for controlling the rotational speed of a motor. The system includes a self-limiting integrator for avoiding or limiting integral wrapup, a problem commonly associated with integral control. The self-limiting integrator includes an integrator, limit comparator, OR gate, delay circuit, and sign reversal circuitry. The integrator reverses direction of integration when an error limit is realized. The error limit, a preestablished and adjustable value, can be used to determine the rise and settle time of the speed of the motor independently of the gain.

Abstract: Special tape drive read circuitry generally qualifies read voltage peaks by establishing a minimum amplitude for valid peaks in the read voltage signal so that noise is not interpreted as peaks, but does not require amplitude qualification during periods of dropout in the read voltage signal. Additional circuitry recognizes two of the data errors most common to GCR, and allows for these errors to be corrected. The first kind of error is the tri-bit error, in which 01110 is misinterpreted as 01000. The other kind of error is the low frequency error, in which 10010 is misinterpreted as 11000. Also, the type of error detected is used to adjust the read drive's hysteresis setting, to reduce future errors of the same type.

Abstract: A closed loop resolution enhancement technique for reducing density effects to permit increased digital data storage density on magnetic media and improve data reliability for at a given density, uses a predetermined test pattern written on the medium to determine the ratio of amplitudes of high and low frequency components of the test pattern and adjust a resolution value. After a test pattern read operation is used to adjust the resolution value, the same value is used during normal data recovery operations.

Abstract: Apparatus and methods involving the use of a prosthetic low pressure reservoir for joint fluid and removal of particulate debris from arthritic joints or joints containing artificial, man-made prostheses. The apparatus filters the fluid and traps any particles therein, thus removing them from the periprosthetic space. A communication is created between a space continuous with the articular surfaces of a joint and a separate extraarticular space. The apparatus connects the space continuous with the articular surfaces of the joint to a fluid reservoir located in the extraarticular space. The reservoir contains means for fluid filtration and particle trapping. The extraarticular location of the reservoir is at a lower pressure than the intraarticular space. Increases in intraarticular joint fluid pressure during normal joint activities will cause fluid and particulate debris to preferentially flow into the low pressure reservoir.

Abstract: The fluid flow meter includes a flexible membrane clamped between upstream and downstream centering springs to enhance membrane behavior and extend the fluid flow measurement range by automatically adaptively moving the apparent clamping points in response to flow rate. Adaptation of the clamping span alters the relative effective excess membrane length within the clamping span to adapt membrane behavior to flow rate. The upstream centering spring includes a long leaf spring pair cantilevered into the clamping span from the clamping region. The long leaf spring pair is sandwiched within a shorter leaf spring pair active at higher flow rates and formed as part of a guide extending to the chamber surface. The membrane ends are narrowed upstream and downstream of the clamping span to reduce flutter while the upstream intake is split into even laminar flows. The fluid direction is substantially changed at the outlet to minimize membrane distortion.

Abstract: A recording target includes targeting information printed on a substrate offset from a visible target and masked from the weapon operator by a thermal clearing masking layer. The operator aims at the visible target and the simulated weapon applies a focussed pulse of intense visible light to the masked targeting information to reveal the relevant targeting information by being converted into infrared radiation, by the thermal clearing masking layer and/or a portion of the masked targeting information thereunder, which clears or renders transparent the portions of the thermal clearing masking layer illuminated by the focussed visible light.

Abstract: A method and apparatus for marring the surface of a fiber optic substrate by feeding the substrate between a pair of rotating rollers. One of the rollers is coated with an abrasive. The second roller may be hard or have a deformable cover. Alternatively, one or both rollers may be serrated to produce a ripple pattern in the substrate. A hydraulic, pneumatic or other device is used for either manually and/or automatically adjusting the gap between the rollers. One or both rollers may also be heated to further enhance the marring action. A cam mechanism may also be used to adjust the pressure in the nip.

Abstract: A system and method for preparing an abraded fiber optic ribbon are provided. This system uses a flat abrasion panel containing a design, such as a company logo, and contacting it directly with a fiber optic ribbon, pressing devices to feed and press the panel and the fiber optic ribbon against each other as the design is being processed onto the fiber optic ribbon, and adjustable speed and differential pressure devices are used to drive the pressing devices. In addition, at least one of the pressing devices may be heated to enhance the processing of the pattern onto the fiber optic ribbon. Particularly, the pressing includes a first roller and a second roller defining a nip through which the panel and the fiber optic ribbon are being fed and pressed against each other. Alternatively, the pressing includes a first plate and a second plate defining a pressing zone in which the panel and the fiber optic ribbon are being fed and pressed against each other.

Abstract: The present invention provides an imaging device and method for developing, duplicating and printing graphic media. The imaging device of the present invention is utilized in devices such as copiers, printers, game cards and the like, and comprises a substrate bearing an infrared image producing layer, a thermal image forming layer and a light source. A brief but intense flash of visible light from the light source causes latent heat properties of the infrared layer to generate heat and convert visible light into far infrared light. This far infrared light develops or marks portions of the thermal layer which are adjacent the infrared layer.

Abstract: A system and method for slowing the data transfer rate in a magnetic tape cartridge drive is presented for a better match in transfer rates between a host computer and the drive. The transfer is slowed after the start of the data transfer operation to selected transfer rates below the nominal transfer rate of the drive. The requirements of density of data on the magnetic tape remains unaffected so that the magnetic tapes are interchangeable with present drives.

Abstract: An improved fiber optic panel having a desired illumination pattern is assembled from at least two partial panels, each comprising a plurality of fully terminated parallel fibers. Two or more such partial arrays are combined to fabricate a optical fiber substrate having an arbitrary illumination pattern. The non-illuminated fiber lengths extending from the individual fiber terminations are removed before the two partial arrays are assembled, thus further enhancing the efficiency of the device. In a preferred embodiment the fibers of each partial array have a center-to-center spacing slightly greater than twice the fiber diameters, and the fibers of the two partial arrays are intermeshed to form a closely packed parallel array of fibers in which a fully terminated shorter fiber is located between two longer fibers.

Abstract: A track following system for maintaining a read gap substantially centered on a data track by moving the read gap perpendicular to the direction of the data track. This moving of the read gap is performed to compensate for any original misalignment between the read gap and data track and also to compensate for any wander or movement of the data track to a misaligned position with respect to the read gap. The write gap is used as a source of position information to keep the read gap correctly positioned over the data track. During a track following operation, the write gap circuitry is operatively connected to a track following circuit. Several samples of data signals received by the write gap are analyzed by the track following circuit. The track following circuit operates to compare a first sample of such data signals with a second sample. A positioning device moves the read gap in a direction determined from the result of this comparison and also from the last direction in which the read gap was moved.