Abstract: The bus system (2) for the transfer of data within a master-slave system (1) comprises a parallel data bus (3) and a serial data bus (4, 5), as well as at least one control line (15, 16) for a control signal (SnP, RnW) determining the manner of transfer, wherein each slave (S.sub.1 . . . n) can be connected to a data bus (3; 4, 5) corresponding to its interface (SIF.sub.p, SIF.sub.S) and can be controlled with respect to the manner of transfer. Upon the transfer of both serial data (SD) and parallel data (PD) with the addressing of the or each slave (Sn), a first control signal (serial, not parallel) for the type of transfer is set before a strobe signal (STRB) for the transfer of data is activated. For the determining of a write or read access, a further control signal (RnW) for the direction of transfer (read, not write) is set.

Abstract: Signal points from a PCM-derived constellation are selected for transmission via a modulation technique which employs different levels of redundancy coding--including the possibility of no redundancy coding--for respective different sub-constellations of the overall PCM-derived constellation. The coding that is employed for at least one of the sub-constellations is carried out independently from any coding that is employed for any of the other sub-constellations. In preferred embodiments, the sub-constellations are non-overlapping portions of the overall PCM-derived constellation, the redundancy codes are trellis codes, and the trellis codes employed in conjunction with sub-constellations having increasingly smaller minimum distance between signal points provide respectively increasing amounts of decibel gain in that minimum distance in order to compensate for that increasingly smaller minimum distance.

Abstract: A low voltage CMOS output buffer protection circuit is configured to protect an associated output buffer from any high voltage signals (e.g., 5V) that may appear along a signal bus line. The protection circuit is also "hot-pluggable", meaning that the protection circuit will not draw any current when not powered (i.e., when VDD is not present). An on-chip reference voltage generator is used to provide a reference voltage VDD2 that will be essentially equal to VDD as long as VDD is present. When VDD is not present, VDD2 will track the signal appearing along the signal bus (PAD), remaining at least two diode drops below the PAD voltage.

Abstract: In accordance with the invention, a switchable optical filter comprises an optical splitter coupled to an input waveguide, one or more output waveguides and a plurality of interferometer waveguides. A multiwavelength signal from the input waveguide is split into plural identical multiwavelength split signals which are directed into the interferometer waveguides. In the interferometer waveguides, a sequence of controllable phase shifters and reflective filters reflects specific wavelength signals from a respective interferometer waveguide into the splitter and then to a respective output waveguide. In a preferred embodiment, the splitting device comprises a directional coupler, and the filter comprises a Mach-Zehnder interferometer with a mid section including an alternating sequence of a phase shifter on at least one arm and reflective filters on each arm. The filter is particularly useful as a gain equalization filter, an ADM filter and in an optical cross connect.

Abstract: A carrier fixture that does not include transport channels or openings for directing a slurry to a substrate being polished. The carrier fixture may have an inner support coupled to a ring member that contacts a substrate during polishing. The carrier fixture may also have outer supports coupled to the ring member. The carrier fixture is used to manufacture integrated circuits.

Abstract: The input buffer of a low-voltage technology integrated circuit (IC) has a buffer transistor adapted to receive an input signal at the gate of the input buffer. The channel nodes of the input buffer are connected to other circuitry (e.g., the low-voltage bias voltage and a current source). With such an input buffer, the low-voltage circuit can safely receive a relatively high input voltage. As such, the low-voltage circuit can be interfaced to and safely operated in conjunction with relatively high-voltage technology circuitry. In one implementation, IC circuitry of existing 5V technology can be safely used with IC circuitry of a new 2.5V technology having an input buffer of the present invention.

Abstract: A head-end dynamically allocates bandwidth of a communications channel as a function of the type of communications traffic. In particular, the head-end communicates to subscriber stations via a broadband cable network using an access protocol, which is modified to provide a variable number of mini-slots and a variable number of data slots in each frame. Each mini-slot is used to request assignment of a data slot(s) to subscriber stations for the communication of information and, also, as a vehicle to resolve contention between subscriber stations. The head-end dynamically adjusts the number of mini-slots over a period time as a function of the type of communications traffic, e.g., bursty and isochronous traffic sources. Any variation in the number of mini-slots concomitantly effects the number of data slots available to communicate information. For example, less mini-slots provides more data slots.

Abstract: Embodiments of the invention include a method for fabricating Bragg reflector gratings using an amplitude mask and an amplitude mask apparatus for fabricating Bragg reflectors. The inventive Bragg reflector gratings have periodicities greater than conventional short period gratings but much less than conventional long period gratings. Short period, Bragg reflector gratings according to embodiments of the invention have periodicities, e.g., within the range from 1 .mu.m to 10 .mu.m. The fabrication method includes positioning an amplitude mask having appropriate slits formed therein over the photosensitive waveguide of interest and then illuminating the waveguide through the slits thereby photoinducing a periodic pattern of refractive index perturbations characteristic of a Bragg reflector. The short period, Bragg grating produced by the inventive amplitude mask is a reflective grating whose reflection characteristics approach approximately 99.99%.

Abstract: A digital speech communication system having improved synchronization. The present digital speech communication system reduces the unit of degradation to a single speech sample, rather than a multi-sample frame, while maintaining the bit rate efficiency of the DSVD system and other systems where speech is encoded into large blocks and is subject to variable delay and mismatched clocks. The basic unit that is dropped or artificially inserted by the receiver, if the buffer overflows or empties, respectively, is reduced to a single speech sample. The speech frames produced by the demultiplexer are written into a frame buffer, in units of frames, at a rate determined by the clock signal, S2, that is extracted from the received signal by a timing recovery function in the modem. In accordance with the present invention, the frames are read out of the buffer into the decoder using the same extracted clock signal, S2. In this manner, once the buffer is partially full, the frame buffer will not overflow or empty.

Abstract: A decoding facility for decoding signal samples characterizing symbols forming a particular pattern. The decoding facility, more particularly, forms the signal samples into groups and each group is decoded into a known symbol. This is done by matching a group of samples with each of a plurality of known symbols and selecting and outputting as the decoded symbol that one of the known symbols that is the closest match to the group of signals being processed.

Abstract: An enhanced Time Slot Interchange (TSI) facility, in addition to serving synchronous channels of communication, decomposes and composes asynchronous data cells to provide real-time communication among and between both synchronous and asynchronous channels served by a network access switch. An asynchronous cell comprises a 5 byte header and a 48 byte payload. The payload comprises voice samples from a temporarily defined set of DSO facilities and/or data from a variety of data facilities. Time slots of the TSI are temporarily assigned to the payload bytes of each incoming asynchronous cell; the payload bytes are stored in memory locations corresponding to those time slots; and the stored data is read out during time slots assigned to the destination channels of communication. The TSI comprises three data rams to accommodate for frame to frame jitter in the time of arrival of payload samples.

Abstract: A high-performance photonic chipset for computing 1-D complex fast Fourier transform (FFT) calculations. Flip-chip integration is used to combine submicron CMOS ICs with GaAs chips containing 2-D arrays of multiple-quantum wells (MQW) diode optical receivers and transmitters on each chip in the set. Centralized free-space optical interconnection offers higher throughput rates, greater external bandwidth and reduced chip count compared to conventional electronic FFT devices using hard-wired interconnection between chips. The memory addressing used provides one-to-one interconnections for memory transfers between computational stages that are compatible with several known three-dimensional free-space optoelectronic packaging technologies and dual-port memory is used to permit simultaneous read-write access to adjacent addresses in the data banks needed by each stage.

Abstract: In an illustrative embodiment, an audio/video conferencing system comprises two or more audio/video terminals, in which the transmitted and/or received audio is automatically adjusted to provide synchronization between audio and video during periods of monologue (i.e., single talker active for significant duration). During interactive periods in which more than one talker is active, the audio delay is automatically adjusted to be less than the video delay, thus improving audio conference quality.

Abstract: An apparatus for preventing misalignment of a plurality of electrically conductive blades for use in a jack interface housing element of a communication plug. The apparatus comprises a locating bar fixedly mounted within the housing. Each blade is engineered with a bifurcated end to form an alignment notch that complements the shape of the locating bar. Thus, aligning the blades for electrical communication with a plurality of jack springs merely requires mating the alignment notches in the blades with the locating bar.

Abstract: A cabling media which is suitable for data transmission with relatively low crosstalk includes a plurality of metallic conductors-pairs, each pair including two plastic insulated metallic conductors which are twisted together. The characterization of the twisting is important and relates to parameters such as twist length as well as core strand length/lay. More specifically, particular combinations of twist lengths and core strand length/lay are purposely selected for each insulated pair of the cable in order to achieve performance capabilities that significantly surpass those required under TIA/EIA-568A. In one particular embodiment of this invention, a cable comprises as its transmission media, four twisted pair of individually insulated conductors with each of the insulated conductors including a metallic conductor and an insulation cover which encloses the metallic conductor.

Abstract: A digital cellular/personal communications service (PCS) application incorporates a logical link connection (LLC) server. In this approach, there are two ATM connections in the path of an AAL-2 connection: one between a base station and the LLC Server and the other between the LLC Server and a vocoder group. All LLCs from, or to, a given base station use a common ATM connection irrespective of the vocoder used at the other end. Similarly, all LLCs from, or to, a given vocoder group use a common ATM connection irrespective of the destination base station at the other end. At the LLC Server, LLC packets from many base stations destined for the same vocoder group are extracted and bundled into the ATM connection between the LLC Server and the destination vocoder group. Similar treatment is given to the packets originating at vocoders and destined for base stations.

Abstract: An enclosure according to this invention comprises a thermally conductive wall mountable to a heat source. The enclosure is mounted such that heat transfers from the heat source to the thermally conductive wall. A bracket holds the item to be heated to at least one of the walls of the enclosure, such that the item is warmed by thermal conduction. A thermal pad may be interposed between the item and the mounting wall and, likewise, between the enclosure and the heat source. By this structure, heat is passed from the heat source to the enclosure and then to the item.

Abstract: Embodiments of the invention include an apparatus and method for stabilizing the operation of lithium niobate devices such as modulators due to charge accumulation caused by, e.g., pyroelectric and piezoelectride effects. The apparatus comprises a substrate having a waveguide formed therein, a buffer layer formed on the substrate, a Si.sub.2 Ti.sub.x N.sub.8/3+x charge dissipation layer (CDL) formed on the buffer layer and a set of electrodes formed on the charge dissipation layer. According to embodiments of the invention, the Si.sub.2 Ti.sub.x N.sub.8/3+x charge dissipation layer has a resistivity of approximately 15-150 k.OMEGA.cm. Alternatively, the apparatus includes a second charge dissipation layer formed on the opposing surface of the substrate. The charge dissipation layer according to embodiments of the invention is advantageous in that it provides a suitable resistivity and is a composition that is easily reproducible using conventional formation techniques such as sputtering.

Abstract: In according with the principles of the present invention, a feedback circuit to compensate for process, temperature, and power supply variations in a typical integrated chip is provided. The feedback circuit increases the accuracy and functionality of an integrated chip by generating an output feedback current that is compensated for process, temperature and power supply variations. The feedback circuit comprises a top current mirror circuit, a bottom current mirror circuit, and a sensory circuit connected to the top current mirror circuit. The sensory circuit continuously senses the variations in the process, temperature and power supply and provides the feedback to top current mirror circuit. The top current mirror adjusts its parameters accordingly and therefore an output feedback current is generated which has necessary compensations for the process, temperature and power supply variations.

Abstract: A method for simulating RF energy distribution comprises obtaining a binary tree representation of a geometric environment in three-dimensions and forming a 3-D geometric database model therefrom, obtaining one or more specified receive locations within the 3-D geometric database model where RF energy distribution is desirable, simulating the propagation of an RF signal within the geometric database model, the RF signal being represented as a beam having magnitude and direction, the propagation including querying the database model to trace the beam in the geometric environment; and, determining one or more intersections of the traced beam with one or more receive locations to determine RF energy distribution at the receive locations.