Abstract: The present invention allows the light beam of an optical disc storage device to radially move between different information tracks of an optical disc while the storage device tracking servo loop remains in a continuous closed loop mode of operation. The invention operates to radially move a light beam from one information track to another during a closed loop mode of operation by activating two control signals introduced into the closed tracking servo loop to create a phantom track center that radially moves across the optical disc. Because the tracking servo loop is in a closed loop mode of operation, the tracking servo operates to keep the light beam centered on the point that the tracking servo considers to be the center of an information track; in this case the phantom track center. Therefore, the tracking servo causes the light beam to radially move across the disc in a closed loop mode of operation by keeping the light beam centered on the moving phantom track center.

Abstract: A flexible strip test cable is disclosed having an elongated flexible strip cable, a series of strip traces disposed lengthwise on the flexible strip cable and having electrical strip contacts near one end of the flexible strip cable, an extension cable integral with the flexible strip cable and having a width at one end greater than the width of the flexible strip cable, and a series of test traces on the extension cable having electrical test contacts near the end of the extension cable remote from the flexible strip cable. Each of the test traces is electrically connected to one of the strip traces, and the minimum distance between two test contacts is greater than the minimum distance between two strip contacts. The flexible strip test cable may have a tooling guide for aligning a cutting tool with the end of the flexible strip cable which is connected to the extension cable.

Abstract: A method for addressing memory uses a word with a fixed width, having a fixed number of bits, and having a width defining field and address field. The procedure is adapted to addressing variable width data. In one embodiment memory can be addressed using a fixed width word having a fixed number of bits, and having both a substitution field and an address field.

Abstract: An integrated digital communication system utilizing multilevel vestigial sideband transmission is provided. The communication system receives a multi-level pulse-amplitude modulated digital signal from a limited bandwidth channel. The system includes processing stages which demodulate, sample and filter the incoming signal prior to recovery of the digital data. Other stages recover the timing and lock on to the frequency and phase of the transmitted signal, as well as provide for automatic gain control. An adaptive equalizer, error correction circuitry, and an output interface recover the digital data and provide for transfer to other devices.

Abstract: An apparatus is disclosed for control of a beam of radiant energy, wherein a detector of the beam has first and second outputs responsive to a position of the beam. A circuit is coupled to the outputs of the detector for producing an error signal representing a displacement of the beam from a predetermined position, wherein the error signal has a periodic characteristic relative to the displacement. A servo responsive to the error signal restores the displaced beam to the predetermined position. A local feedback loop is coupled to the outputs of the detector, and includes first and second periodic function generators, each responsive to the error signal. The second periodic function generator has an output that differs from an output of the first periodic function generator by a phase angle, preferably 90 degrees. A first multiplier multiplies the first output of the detector by the output of the first periodic function generator.

Abstract: This invention provides a method to control the buffering of encoded video data organized as frames or fields. This method involves determining the picture number of each incoming decoded frame, determining the expected presentation number at any time and marking any buffer as ready when its picture number is on or after the presentation number.

Abstract: The mechanism for loading and unloading a disk cartridge uses two sliders (one on each side of a base plate), which move in opposite directions under the influence of a tiller. Each slider has a slot to receive one of the two lifting pins provided on the cartridge receiver. The movement of the sliders drives the lifting pins along the slots, thereby raising or lowering the cartridge receiver depending upon the direction of rotation of the tiller. The sliding motion of the lifting pins engaged in the S-shaped slots thus unloads a disk from or, alternatively, loads the disk onto the drive spindle. As the lifting pins travel along their respective slots, the lifting and lowering of the disk is accomplished in such a manner that the disk hub is peeled from the spindle magnet rather than being lifted vertically off the spindle. This reduces the peak force required to break the magnetic clamp force between the spindle magnet and the disk hub.

Abstract: A first write encoder encodes digital data in a first, high-density format. A second write encoder encodes digital data in a second, low-density (i.e., ANSI) format. A first read decoder decodes digital data from the first format. A second read decoder decodes digital data from the second format. A disk drive receives a replaceable 90 millimeter optical disk. A read/write head reads encoded data from and writes encoded data to a 90 millimeter optical disk received by the drive. In a first mode, the first write encoder is connected between a source of digital data and the read/write head, and the first read decoder is connected between the read/write head and the utilizing apparatus. In a second mode, the second write encoder is connected between the source and the read/write head, and the second read decoder is connected between the read/write head and the utilizing apparatus.

Abstract: An improved phase locked loop utilizing control logic generated by a phase detector to eliminate sensitivity to uncorrelated noise when the loop is in lock.

Abstract: A method for moving a carriage assembly from an initial position to a target position relative to a storage medium rotating at a circumferential velocity. The method includes the steps of determining a first radial distance between the initial position and a center of the storage medium, determining a second radial distance between the target position and the center of the storage medium, determining a circumferential distance between the initial position and the target position, determining an initial circumferential velocity of the storage medium, calculating a velocity trajectory relative to the first radial distance, the second radial distance, the circumferential distance, and the initial circumferential velocity, and moving the carriage assembly from the initial position to the target position substantially at the velocity trajectory. The velocity trajectory is calculated such that the carriage assembly will arrive radially and circumferentially at the target position at substantially the same time.

Abstract: An adjustable optical system for determining aberration in a source beam by comparison of a test beam with a reference beam. The system includes a test source for producing a source beam having a spacial intensity distribution including an aberration component, a wavefront analyzer for processing a fringe signal associated with the aberration component, and an interferometer interposed between the test source and wavefront analyzer. The interferometer includes a beamsplitter for splitting the source beam into a test beam and a reference beam, a mirror disposed in the test beam path, and a micromirror disposed in the reference beam path. The micromirror reflects a central portion of the reference beam toward an imaging device and allows an outer portion of the reference beam to pass thereby.

Abstract: An integrated digital communication system utilizing multilevel vestigial sideband transmission is provided. The communication system receives a multi-level pulse-amplitude modulated digital signal from a limited bandwidth channel. The system includes processing stages which demodulate, sample and filter the incoming signal prior to recovery of the digital data. Other stages recover the timing and lock on to the frequency and phase of the transmitted signal, as well as provide for automatic gain control. An adaptive equalizer, error correction circuitry, and an output interface recover the digital data and provide for transfer to other devices.

Abstract: There is disclosed an apparatus for controlling the strength of a magnetic field, comprising a first controller, a second controller, a digital-to-analog converter, a current driver, and a bias coil. The first controller determines the position of the focal point of a lens and passes it to the second controller, which provides a digital signal related to the position. The digital-to-analog converter converts the digital signal to a driver voltage and passes the driver voltage to a current driver, which provides to the bias coil a bias current related to the driver voltage. The bias coil produces a magnetic field having a strength related to the bias current. The second controller accounts for stray magnetic fields in creating the digital signal. The stray magnetic fields may be constant or may vary in strength based on position of the objective lens, circumferential velocity of the storage medium, or longitudinal velocity of the storage medium.

Abstract: An apparatus for moving an optical head from an initial track to a target track on a storage medium and generating a track crossing signal is disclosed. The apparatus comprises a sensor for measuring the reflectivity level from a storage medium, a preamplifier for generating a data signal, a tracking error signal generator responsive to the reflectivity level for deriving a tracking error signal, a track/hold selector to direct the tracking error signal generator to generate a corrected tracking error signal of a constant amplitude for a predetermined period of time based on the data signal, and a track crossing signal generator based on the corrected tracking error signal for deriving a track crossing signal indicating the crossing of an information track by the optical head.

Abstract: A method for detecting transitions in an input signal having a DC component. The method includes the steps of generating a threshold signal from the input signal, comparing the input signal to the threshold signal to thereby generate an output signal, and adjusting the threshold signal in response to the output signal. In one preferred embodiment, the method is employed to retrieve data from an information storage device.

Abstract: An optical beamsplitter comprises a right angle prism having a hypotenuse and two legs wherein the hypotenuse includes an optically selective coating deposited thereon. An optical element is positioned adjacent the hypotenuse such that the hypotenuse and the optical element form a beamsplitting interface. Various optical elements are utilized to achieve the desired spatial and angular relationships between incoming and outgoing light beams. Several embodiments are disclosed wherein the optical element can comprise a flat plate for providing spatial offset, a wedged plate for producing spatial and angular offset, a lens for adding optical power, or a faceted thin plate.

Abstract: An optical beamsplitter comprises a right angle prism having a hypotenuse and two legs wherein the hypotenuse includes an optically selective coating deposited thereon. An optical element is positioned adjacent the hypotenuse such that the hypotenuse and the optical element form a beamsplitting interface. Various optical elements are utilized to achieve the desired spatial and angular relationships between incoming and outgoing light beams. Several embodiments are disclosed wherein the optical element can comprise a flat plate for providing spatial offset, a wedged plate for producing spatial and angular offset, a lens for adding optical power, or a faceted thin plate.

Abstract: An optical beamsplitter comprises a right angle prism having a hypotenuse and two legs wherein the hypotenuse includes an optically selective coating deposited thereon. An optical element is positioned adjacent the hypotenuse such that the hypotenuse and the optical element form a beamsplitting interface. Various optical elements are utilized to achieve the desired spatial and angular relationships between incoming and outgoing light beams. Several embodiments are disclosed wherein the optical element can comprise a flat plate for providing spatial offset, a wedged plate for producing spatial and angular offset, a lens for adding optical power, or a faceted thin plate.

Abstract: A high speed analog-to-digital converter employs a comparator having first and second units cross coupled in a positive feedback loop. The units are alternately connected to an input voltage and a reference voltage, after which positive feedback is introduced established, and a differential output established. The arrangement is fully symmetric, and balanced and rejects common-mode switching noise.

Abstract: An apparatus is disclosed for processing video information using a first and a second prediction filter circuit which are substantially identical, and a control signal to process video information encoded in multiple standards. A filter circuit, such as may be used in such an apparatus, for use in video decompression comprises a prediction filter formatter, a first one-dimensional prediction filter, a dimension buffer, and a second one-dimensional prediction filter. A prediction filter, such as may be used in such a filter circuit, may comprise six registers, two multiplexers, and two summing circuits. A first register is connected to a first summing circuit. A second register is connected to a first multiplexer, which is connected to the first summing circuit. The first summing circuit is connected to a third register. A fourth register is connected to a second multiplexer, which is connected to a fifth register.