Abstract: The routing of signals in a telecommunication network 100' comprising a plurality of interconnected nodes 102, 103, 104, 104', 105, 106, 106' and 107, such as a SONET ring network, is modified through use of a controller 160. The controller 160 maintains a mapping between the telephone numbers of subscriber locations 132, 138, and the network nodes 104', 106' to Which the subscriber locations are attached The ring controller 160 permits a subscriber location to change the node to which it is attached without changing its telephone number. Utilizing the ring controller, new services such as ISDN, can be offered to a large body of potential subscribers while only a limited number of central offices are actually upgraded.

Abstract: A digital decision feedback equalizer utilizes a finite impulse response (FIR) filter and an infinite impulse response (IIR) filter in parallel in the feedback path. The FIR filter compensates for the rapidly changing region of the channel impulse response immediately following the cursor while the IIR filter compensates for the gradually decaying tail of the impulse response of the channel. Modifications of a sequential identification algorithm are used to adapt the filter sections. In particular, in one modification, the inputs to both the poles and zeros sections of the IIR filter are prefiltered by an all-pole filter, where the poles of this filter are the current pole estimates. In another modification, the order of the zeros section of the IIR filter and the all-pole filter are reversed, and the zeros section is adapted using the least mean squares algorithm. A recursive least squares algorithm with exponential fading can be used to adapt the poles and/or zeros section of the IIR filter.

Abstract: A method and apparatus for highly efficient use of higher-order diffraction beam in holography. The thermoplastic hologram (10) is recorded at a recording angle (.theta..sub.R) between two coherent beams (12, 14) equal to a first-order diffraction angle (.theta..sub.1) corresponding to the angle (.theta..sub.2) of the desired higher-order beam (18) set to the angular peak (22) of diffraction efficiency (20) of the material of the hologram. On read-out, the desired higher-order beam is read. By use of the invention, the intensity of a higher-order beam can be tuned and made nearly equal to that of the first-order beam. Thereby, useful non-linear holographic systems, such as an associative memory (FIG. 4), can be practically implemented.

Abstract: A reactor cell for use in organo-metallic chemical vapor deposition (OMCVD). Multiple precursor gases are combined in a supply tube (14). A deflector section (56) connected to the supply tube consists of three tubes (58, 60, 61) joined at right angles to each other and to the supply tube in order to maximize the turbulence in the gas flow and to thereby uniformly mix the gas. The last of the three tubes is perpendicularly joined to a tapered section (30) of rectangular cross-section that tapers outwardly toward a deposition chamber (22) of rectangular cross section containing a heated susceptor (18) holding the wafer (20) over which the uniformly mixed gas flows and cracks, thereby epitaxially depositing some of its constituents on the wafer.

Abstract: A technique for all-optical Code Division Multiple Access (CDMA) system based on optical holography is disclosed. In this technique the energy of an incoming information light signal is spread over a spatial domain by a two-dimensional spatial encoder which includes a mask having regions of first and second transmission characteristics corresponding to the unique code assigned to a particular source. Subsequent decoding, which is accomplished by an optical matched filter through the use of a hologram, spatially despreads the energy of the information light signal and produces a focused light beam which serves as input to a code division detector.

Abstract: An apparatus for performing storage and retrieval in an information storage system is disclosed which uses the hashing technique. In order to provide efficient and graceful operation under varying loading conditions, the system shifts between collision avoidance by linear probing with open addressing when the load is below a threshold, and collision avoidance by external chaining when the load is above a threshold. Insertion, deletion and retrieval operations are arranged to switch dynamically between the two collision avoidance stratagems as the local loading factor on the system, as measured by the number of records hashed to the same address, crosses preselected thresholds.

Abstract: A queue management method and system manages queued cells in such a way that higher priority cells are always served first, the low priority cells are dropped when the queue is full and, within the same priority, any interference is prevented. Four different architecture designs for such queue management are presented and their implementation feasibility and hardware complexity are compared and contrasted. A departure sequence is assigned to each cell in the novel architecture to implement the queue management. The sequence applies the concepts of fully distributed and highly parallel processing to schedule cell sending or dropping sequences. Preferably, a sequencer is provided such that the queue size and the number of priority levels can grow flexibly and without limit.

Abstract: A method of forming crystalline metal oxide thin films on silicon and the resultant structure. A crystalline buffer layer (10) of yttria-stabilized zirconia is deposited on a silicon substrate (12). A thin template layer (10) of an anisotropic perovskite such as bismuth titanate or yttria barium copper oxide is deposited on the template layer under conditions favoring c-axis oriented growth. A nominally cubic metal-oxide layer (16) is deposited on the template layer which facilitates its singly crystalline growth. The metal oxide, often a nominally cubic perovskite, may be a conductive electrode, a ferroelectric, a non-hysteretic dielectric, a piezoelectric, or other class of material.

Abstract: A method of fabricating a self-aligned gated electron field emitter. An oxidation process forms an optimized, atomically sharp needle (18) in a silicon substrate (12). The needle and surrounding planar area are conformally coated with silicon dioxide (22). A dielectric layer (24) is deposited and planarized over the needle. The dielectric layer is then partially etched away so as to expose the coated needle. The silicon dioxide exposed on the needle is isotropically etched so as to undercut the dielectric layer. A gate metal is directionally deposited so as to form a gate layer (26) on the planar portions of the dielectric layer that is electrically isolated from the gate metal (28) deposited on the needle. The metal on the needle is anodically etched by applying the potential only to the silicon and not to the gate layer. Electro-plating may recoat the needle with another metal (30).

Abstract: A saturable absorber comprising multiple quantum-well layers (32, 34, 36) of differing thicknesses and separated by barrier layers (38) so as to produce a wide-band absorption. Such a saturable absorber (30) is useful in a hybrid mode-locked laser having an optical cavity defined by two mirrors (10, 12) into which are placed the saturable absorber (30) and an optical amplifier (14) driven by both a DC bias and an RF modulation signal.

Abstract: In accordance with the present invention, the number of bits used to code a frame of video is controlled by controlling the frame size. In a preprocessing stage (40) of a video coding circuit (10), each frame of video is processed by a low pass anti-aliasing filter (43,44) in the horizontal and vertical directions. The cutoff frequencies in the horizontal and vertical directions are determined by a desired frame reduction factor in the corresponding direction. Then to reduce the sampling rate in each dimension, each frame of video is processed horizontally and vertically by a shift varying filter (45,46). When the sampling rate in both the horizontal and vertical directions is reduced by M/N, the number of code bits decreases linearly with M/N.

Abstract: An apparatus and method for measuring conductive airborne particulates in which a filter (16) having a pair of interdigitated electrodes (18, 20) printed on its surface is placed in a sampling chamber (14). A pump (10) draws air (12) through the chamber and through the filter with airborne particles being deposited on the side of the filter with the electrodes. The resistance between the electrodes is measured (22) without removing the filter from the chamber.

Abstract: A III-V semiconductor heterojunction in which a capping layer (14) is formed between the two layers (10, 16) of the heterojunction to prevent any deleterious effects due to As--P exchange. When InAlAs is grown on InP, the capping layer is AlP. When GaAs is grown on GaInP, the capping layer is GaP.

Abstract: A method for coding frames of video wherein a coding circuit (14,16,18) includes a processor (30) for performing an orthogonal transform such as a discretecosine transform and a quantizer (32) for quantizing the resulting transform coefficients. The coding circuit codes the video frames using intra-frame, predictive or interpolative coding to generate code bits at a variable rate. The code bits are stored at a variable rate in a rate buffer (22), which transmits the code bits into a communication channel (24) at a pseudo-constant rate, i.e. a rate which is constant in every time interval of one frame. To maintain the contents of the rate buffer (22) within predetermined limits, the quantization parameters utilized by the quantizer (32) are periodically adjusted to increase or decrease the amount of code bits generated by the coding circuit.

Abstract: A network (10) for providing cross-context connections between subscribers comprises a plurality of directory databases for storing mappings between individual names, addresses and personal identification numbers of network subscribers in a plurality of telecommunications contexts such as business, residence, cellular, etc. The network (10) also comprises a linking database comprising one entry for each subscriber. Each entry of the linking database is accessed by the personal identification number of a subscriber and contains pointers to particular ones of the directory databases where the addresses for the subscriber in different contexts can be found. For example, to set up a cross-context connection, a first subscriber (A) who knows the address of a second subscriber (B) in one context, transmits the known address to a directory controller (70).

Abstract: A merging network which receives three or more simultaneous input lists of sorted numbers and merges the input lists to form a single sorted list at its outputs. The merging network comprises three stages of interconnected comparator modules, the merging network inputs being connected to the inputs of the comparator modules of the first stage with a mod shuffle interconnection pattern. The outputs of the third stage form the network outputs of the merging network. The first, second, and third stages include one or more comparator modules which are larger than two-by-two. The inventive merging network may be utilized recursively to form a sorting network.

Abstract: A relatively simple optical monitoring technique is utilized to measure temperature within a processing chamber. A III-V direct-bandgap semiconductor is optically excited to emit photoluminescence (PL). Spectral resolution of the emitted PL provides a direct measure of the bandgap of the semiconductor. In turn, the temperature of the semiconductor is derived from the bandgap measurement.

Abstract: A method and apparatus for updating application databases in real time in a distributed transaction processing environment, such as a service control point, without adversely affecting the throughput of transaction processing or losing substantially any conversational transactions that are being processed while updating is occurring. Specifically, two versions, e.g. an old and a new version, of the application databases exist within a memory device, e.g. a shared disk farm. After the start of a "transfer time period", all transactional messages associated with transactions that were initiated after the start of this period are processed using only the new versions of the application databases, while all transactional messages that are associated with transactions that were initiated prior to the start of this period are processed using the old versions thereof.

Abstract: Tapered silicon structures, of interest for use, e.g., in atomic force microscopes, in field-emission devices, and in solid-state devices are made using silicon processing technology. Resulting tapered structures have, at their tip, a radius of curvature of 10 nanometers or less.

Abstract: Tapered silicon structures, of interest for use, e.g., in atomic force microscopes, in field-emission devices, and in solid state devices are made using silicon processing technology. Resulting tapered structures have, at their tip, a radius of curvature of 10 nanometers or less. Such preferred silicon structures are particularly suited as electron emitters in display devices.