Abstract: An technique is disclosed for focus 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 focus 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: A mechanical isolation apparatus suited for mitigating the effects of undesired mechanical forces upon disc drive system components, such as those found in compact disc, laser disc, magneto-optical player/recorder devices and similar devices. Component members are provided for mitigating the effects of compressive forces, vibration isolation, and thermal expansion, and may include compression ribs mounted on a housing for absorbing compressive forces. The housing is preferably adapted to fit on the end of a pole piece assembly. A crash stop may also be provided as a shock absorbing bumper and isolator to prevent a moving carriage from crashing into a solid surface. The compressive ribs and the crash stop are made of a material that exhibits minimum creep, such as a silicon rubber, polyurethane, or injection molded plastic.

Abstract: A pipeline structure processes data in a series of stages, each of which has a data input latch (LDIN) and passes it on to the next stage in the pipeline via a data output latch (LDOUT). The stages are preferably connected to two non-overlapping clock phases (PH0, PH1) Adjacent stages are also connected via a validation line (IN.sub.-- VALID, OUT.sub.-- VALID) and an acceptance line (IN.sub.-- ACCEPT, OUT.sub.-- ACCEPT), and in some embodiments also via an extension bit line (IN.sub.-- EXTN, OUT.sub.-- EXTN). Input data is transferred from any stage to the following device on every complete period of both clock signals only if both the validation and acceptance signals in the respective latch are in an affirmative state, whereby data is transferred between stages regardless of the state of the validation and acceptance signals in other stages. A two-wire interface is thus formed between the stages.

Abstract: An MPEG decoder operates in 2.5 frame store mode, and has an efficient memory management which allows a B picture to be stored and displayed while simultaneously making use of a portion of the frame store memory. The video frame is treated as a grid, having rows of 8.times.8 pixel blocks. The pixel blocks are manipulated in three FIFOs which are cross-connected in a closed loop. Two processes operate on the memory so arranged: (1) a video reconstruction process which writes data into the memory, and (2) a display process, which accesses the memory and writes the video frame into another, external memory in a rastered format. One of the three cross-coupled FIFOs is designated for write-back, and the other two for reading 2:1 interlaced raster data. The two FIFOs utilized for the raster operation are allocated to the alternate lines of the picture.

Abstract: A multi-standard video decompression apparatus has a plurality of stages interconnected by a two-wire interface arranged as a pipeline processing machine. Control tokens and DATA Tokens pass over the single two-wire interface for carrying both control and data in token format. A token decode circuit is positioned in certain of the stages for recognizing certain of the tokens as control tokens pertinent to that stage and for passing unrecognized control tokens along the pipeline. Reconfiguration processing circuits are positioned in selected stages and are responsive to a recognized control token for reconfiguring such stage to handle an identified DATA Token. A wide variety of unique supporting subsystem circuitry and processing techniques are disclosed for implementing the system.

Abstract: An apparatus for aligning an actuator lens within a baseplate using a beam of radiant energy. The actuator lens has an actuator optical axis and an actuator optical center and the apparatus includes a frame, a cradle, a tower assembly, a lever assembly, and a gripper assembly. The cradle assembly is employed to hold the baseplate and is mounted to the frame with at least one degree of freedom of motion. The tower assembly defines a tower axis and is also mounted to the frame. The cradle and tower assemblies are positioned to receive the beam of radiant energy along the tower axis and analyze a spot profile of the beam. The lever assembly is rotatably mounted to the frame and the gripper assembly is mounted to the lever assembly.

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 embodiment of a cell culture system has a cell death accelerator comprising one or more cell death inducing substances, including serum albumin, hemoglobin, glycine and glutamic acid. In a second embodiment a cell death inhibitor comprises one or more kinds of cell death inhibiting substances which include mercapto group containing amino acids, other mercapto group containing compounds and tryptophan. In a third embodiment a cell death inhibitor comprises an inhibitor of RNA or protein synthesis, optionally augmented with a thiol. The system can be applied to selectively induce death of cultured cells, such as neoplastic cell lines, or to inhibit death of other cells, such as neoplastic cell lines or non-neoplastic cells such as brain cells.

Abstract: Control apparatus and method are disclosed for shifting focus on a multilayered optical medium using closed loop servo operation. The outputs of an astigmatic optical pickup are independently modified by a control signal generator according to a predetermined time varying pattern to produce a deceptive error signal that changes the apparent focal offset seen by a servo circuit. While in closed loop mode, the servo tracks the shifting apparent focal plane from a first information layer of the medium toward a second information layer. Thereafter the control signals are removed, and the servo locks focus on the second information region.

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: An apparatus for moving a carriage assembly from an initial position to a target position relative to a storage medium rotating at a circumferential velocity. The apparatus includes a suspended body having a center of mass and a lens defining an optical axis. The center of mass being disposed substantially on the optical axis. The carriage assembly suspends the suspended body and has a center of mass on the optical axis proximate the center of mass of the suspended body. A drive producing a plurality of balanced and symmetrical forces moves the carriage assembly from the initial position to the target position. A processor determines a velocity trajectory relative to the radial distance of the initial position and the target position to the center of the medium, the circumferential distance between the initial position and the target position, and the initial circumferential velocity of the medium.

Abstract: A positioning system for locating objects in places where standard Global Position System signals do not penetrate. A first embodiment uses a GPS receiver and a clock recovery unit. A computer receives the positional information and accurate time information. The computer calculates new orbital data for at least four pseudosatellites. The pseudosatellites are antennas positioned in an interior or shielded space and function to send pseudosatellite data to a receiver. In a second embodiment, the positions of the pseudosatellites are provided to the computer without the use of a GPS receiver. An accurate clock signal is also provided. The computer calculates orbital data for each pseudosatellite and transmits the time signal and ephemeris data for each pseudosatellite. The time signal is delayed for each pseudosatellite to account for propagation delays due to different connecting cable lengths.

Abstract: A method and apparatus are disclosed for determining the boundaries of guard intervals of data symbols being received in a coded orthogonal frequency division multiplexed signal. Temporal samples separated by an interval of an active interval of a data symbol are associated in pairs, and difference signals obtained. The dispersion of a first comparison block of difference signals is determined, and compared to the dispersion of a second comparison block of difference signals, the second comparison block being displaced from the first comparison block by n samples. An F ratio is calculated for the dispersions of the two blocks. F ratios are iterated in a succession of comparison blocks, and a signal representing the F ratios subjected to peak detection. The peaks represent the boundaries of the symbol's guard interval. This information is utilized in synchronizing an FFT window for subsequent signal reconstruction.