Abstract: Indium is employed as the shallow portion of a lightly doped drain transistor.

Abstract: A synchronization control scheme that provides a drive signal to a plurality of switching circuits and method of operation therefor.

Abstract: The present invention is a signaling and control architecture for establishing a connection between mobile users in a wireless ATM LAN. The ATM LAN includes a plurality of portable base station (PBS) switching nodes coupled together to enable communication between said nodes, wherein the nodes are configurable in an arbitrary topology to form an ad-hoc network. The present invention includes network management techniques for configuration of data tables used for connection control. Mobility management techniques are disclosed to handle mobile sign-ons and idle handoffs, locate mobile users during connection and setup and perform handoffs when a mobile is actively involved in a connection. Connection control procedures are also included for setting up and releasing connections on demand.

Abstract: A digital audio broadcasting (DAB) system includes a radio-frequency (RF) receiver that develops a characterization signal representative of a respective mobile communications channel as a precursor to estimating a channel impulse response. The latter is used to set coefficients of an equalizer of the receiver to compensate for distortion such as intersymbol interference. In generating the channel impulse response a Fast Fourier Transform (FFT) of the characterization signal is performed. The resulting FFT is then clipped such that frequency components above a predetermined upper threshold and less than a predetermined lower threshold are set to the respective threshold values. This allows coefficients for the equalizer to be generated such that the equalizer converges even in the presence of strong reflections in a mobile communications environment.

Abstract: A smart card, a non-passive, secure, microprocessor based data storage medium, is used for the storage of a plurality of data messages and is read by a video telephone terminal equipped with a smart card reader to provide transmission of a data message, comprising video image data, either in still frame or full motion format, to a remote video telephone terminal. The use of the smart card for storage of a data message provides a secure, transportable message that is available for transmission from any video telephone terminal having smart card reading capability.

Abstract: A clad optical fiber comprising a core and a cladding made of a material having a refractive index smaller than that of the core, wherein the cladding is made of a cured material comprising a perfluoropolyether or perfluorohydrocarbon backbone end capped with (meth)acrylate groups via urethane groups.

Abstract: Systems and methods for steering an optical path to gain access to data locations in a holographic memory cell (HMC). One of the systems includes: (1) a reflective element, locatable proximate a first focal plane of a complex, spatially-modulated incident beam of light, (2) a polar steering mechanism, coupled to the reflective element, that orients the reflective element according to desired tilt and precession angles to steer the incident beam in a desired direction and (3) a refractive element that refracts the beam reflected from the reflective element to create a second focal plane for the beam, the HMC locatable proximate the second focal plane to receive the beam at a location thereon that is a function of the desired direction.

Abstract: A phase recovery circuit consists of a tapped delay line created by a string of inverters where taps are taken at every other inverter. To initialize the circuit, each tap loads a signal sample into a holding register where the holding register consists of a flip-flop connected to each tap. The flip-flops are loaded by the active edges of the system clock such that each flip-flop contains a sample of data at a given point in time. The sample register delivers the data to a processor that periodically creates histograms of the signal to determine the signal transition points between adjacent bits and the number of taps between the transition points that define a bit. Once the transition points are known, the center of the bit to be latched is located and the tap nearest the center of the bit is used to latch the data for delivery to the next downstream location. From the histograms the processor can also determine if the signal is shifting relative to the system clock.

Abstract: Methods and systems for non-invasive RF circuit testing, and/or for RF signal redirection, are disclosed. These methods and systems are used in conjunction with an RF circuit having a first circuit element, a second circuit element, a microstrip line coupling the first circuit element to the second circuit element, such that RF power flows along the microstrip line from the first circuit element to the second circuit element, and an RF test port for testing the RF circuit. A first removable electrical impedance is placed in physical proximity to the microstrip line to produce a first impedance mismatch at the microstrip line, such that some RF power is reflected by the mismatch back to the first circuit element. A second removable electrical impedance is placed in physical proximity to the microstrip line, such that the microstrip line is coupled to the RF test port.

Abstract: A device for securing a telecommunications cable includes a mid-section and side sections extending from the mid-section for receiving a telecommunications cable. During installation, a "base" cable securing device is positioned on a telecommunications cable and adheres to a stationary object. A "grow" cable securing device surrounds a portion of a second telecommunications cable and is positioned to interlock with the base device to form a stable bundle of telecommunications cables.

Abstract: The present invention includes a system for tracing jumpers used in an exchange to cross-connect optical fibers or wires served by the exchange. The system includes an exchange housing receptacles with optically-encoded data associated with each receptacle or a group of receptacles. The optically-encoded data for a receptacle(s) uniquely identifies the physical location of the receptacle from any other receptacle in the exchange. Likewise, the jumpers each have optically-encoded data formed thereon that uniquely identifies the jumper or jumper end and distinguishes the jumper from any other jumper used in the exchange. If no jumper is to be connected to a particular receptacle, a cover with optically-encoded data can be attached to a receptacle to indicate that no jumper is connected to the receptacle.

Abstract: A time delay device for an optical signal wherein an optical frequency comb is generated by a comb generation device. The optical frequency comb consists of a plurality of discrete and temporally spaced optical channels or carriers. The separation of the channels is dictated by the shifting frequency applied to the comb generation device and the temporal spacing is defined by the length of fiber used so that a time delay is created for each traverse of the fiber loop by the optical frequency comb. A filter connected to the comb generation device is used for tuning to a particular frequency or channel in the optical comb to obtain an optical signal having a desired time delay.

Abstract: The present invention provides synchronization of logic signals in a digital system using optical pulses generated from optical modulators. In one embodiment of the present invention, electrically driven optical modulators are positioned at electrical outputs of interest, and the modulators are read out in accordance with synchronized optical pulses produced from a timing source, where the optical pulse lengths are relatively short compared to the electrical output pulse length. The resulting modulated optical pulses output from the optical modulators are then all once more synchronous, with the skew in the original electrical signals having been removed. These optical pulses can then be communicated over optical channels, such as fiber or free space, with well controlled delay, thereby also reducing problems of variable delay in electrical connections.

Abstract: An optical amplifier achieves multistage amplification with a four port optical circulator with fiber amplifiers and Faraday rotators and mirrors connected to at least two of the ports. The fiber amplifiers permit the signal to pass through the fiber amplifiers twice.

Abstract: An optical groundwire includes an organizer made of glass fibers held together in a matrix. A plurality of core tubes containing optical fibers are retained within the organizer. A plurality of conductors are wrapped about the organizer to form a sheath.

Abstract: A walk-off device comprising a birefringent or uniaxial material achieves increased spatial separation of the ordinary and extraordinary beams by using at least one face of the device for reflection. The two beams are folded and path length increased within the device; the folding increases the spatial separation of the beams when they exit from the device as compared to a device in which the beams are not folded. The reflection face is oriented either parallel or perpendicular to the optic axis of the material.

Abstract: An optical terminator 100 is designed to make end-to-end contact with an optical fiber whose end portion is held within a cylindrical ferrule. The optical terminator reduces reflections that occur when an optical path encounters an abrupt change in refractive index (e.g., when the end portion of the optical fiber encounters an air gap whose refractive index n.apprxeq.1.0). The optical terminator includes a generally cylindrical member 110 that projects from, and is supported by, a backbone member 120. The cylindrical member and the backbone member are molded from polymethyl methacrylate (PMMA) as a one-piece structure. PMMA provides a reflection of about -40 dB. Nevertheless, plastic materials having an index of refraction of 1.46.+-.0.06 produce reflections that are less than about -34 dB, which is acceptable in a large number of applications. Moreover, plastic materials having a glass-transition temperature (T.sub.g) that is higher than about 80.degree. C.

Abstract: Apparatus and methods for machine learning the hypotheses used in the classifier component of pattern classification devices such as OCRs, other image analysis systems, and and text retrieval systems. The apparatus and methods employ machine learning techniques for generating weak hypotheses from a set of examples of the patterns to be recognized and then evaluate the resulting hypothesis against example patterns. The results of the evaluation are used to increase the probability that the examples used to generate the next weak hypothesis are ones which the previous weak hypothesis did not correctly classify. The results of the evaluation are also used to give a weight to each weak hypothesis. A strong hypothesis is then made by combining the weak hypotheses according to their weights.

Abstract: Methods and apparatus for controlling signal line impedance in an electronic circuit board by altering the characteristics of a grid-like ground plane. The ground plane is arranged adjacent and parallel to a signal plane of the circuit board, and includes a grid-like pattern of conductors. The grid-like pattern of conductors forms a large number of grid elements. The size of the grid elements in a portion of the ground plane varies along at least a portion of the length of a corresponding signal trace of the signal plane in order to provide a desired impedance for the signal trace. The grid element size variation may be in accordance with a ramp function, a staircase function, a square wave function, as well as suitable combinations of these and other functions. This variation of grid element size in a grid-like ground plane provides cost-effective and flexible control of signal trace impedance, without requiring any alteration in signal trace or dielectric material characteristics.

Abstract: A coaxial cable has an inner conductor coated with a first dielectric material and which is surrounded and encased in a second dielectric material having a lower dielectric constant than the first material. The layer formed by the second dielectric material is surrounded by a layer of insulating material having a higher dielectric constant than that of the second material which preferably is in the form of a helically wound tape which is adhesively bonded or heat sealed over the second material. An outer conductor surrounds the layer of insulating material, and the entire assembly is encased in an outer jacket of insulating material.