Abstract: Disclosed are methods and associated devices for minimizing the undesirable affects of interference signals in the upstream spectrum of an multiuser interactive system. The method comprises receiving an initial upstream signal at a multiuser interactive processor in a multiuser interactive system. The frequency of the initial upstream signal is at a frequency within the upstream spectrum. Next, the multiuser interactive processor determines a measure of interference associated with at least a portion of the upstream spectrum. Based upon the measure of interference, an upstream channel, from within the upstream spectrum, is selected. The upstream channel is within the upstream spectrum. Finally, the multiuser interactive processor transmits a second signal representative of the upstream channel.

Abstract: According to this invention, the system prepares user data into blocks of manageable size prior to software distribution. A block is similar in principle to memory pages in a file management system and has a predefined size, sequential ordering, and layout from which the original information can be reconstructed. The broadcast protocol is enhanced to include a block identifier to identify where the receiver performs error detection and error correction on each block. Station receiving the data maintains a list of the identity of those blocks of data that it believes have not been received properly. With each retransmission, each work station attempts to receive and recover those blocks marked on its list. Advantageously, each transmitted block is encoded using forward error correction in order to further enhance the probability of proper reception of the data.

Abstract: A highly accurate apparatus and method of predicting remaining capacity Q and reserve time t of a discharging battery to a selected end voltage is determined by an arrangement considering the open circuit voltage, battery voltage, battery temperature and its internal resistance. The remaining battery capacity Q is determined from the difference between the battery full charge open circuit voltage Eoc and the voltage loss due to the internal resistance of the battery IRint and the battery voltage on discharge divided by the battery temperature T, which is the temperature-corrected battery overvoltage.

Abstract: The present invention provides methods and apparatus for analyzing the particulate contents of a sample such that a high proportion of the sample particles are analyzed without discrimination against high electronegativity and high ionization potential elements. In an exemplary embodiment, the invention comprises an apparatus for analyzing the particulate content of a sample having particulate diameters in range of 0.001-10 microns. The apparatus comprises an evacuable chamber equipped with a chamber entrance through which a particle-laden gas stream enters. An inlet device, such as a capillary, communicates with the chamber entrance for inputting the particle-laden gas stream to the evacuable chamber. A laser is positioned to produce a focused laser beam which intersects the particle-laden gas stream at a position approximately 0.1 mm from the chamber entrance. The laser beam has a power density sufficient to fragment and ionize particles entrained within the particle-laden gas stream.

Abstract: An apparatus and method provides optical multiple wavelength signals using a single optical broadband source to generate many independent optical wavelength channels. An optical transmitter includes a pulse chirping device which separates the frequency components of periodic optical pulses in the time domain forming separate wavelength channels which are separately modulated by a high-speed broadband optical modulator. A receiver includes a passive splitter to separate the individual wavelength channels. The chirped-pulse transmitter can then be conveniently adjusted to provide optimum overlap of wavelength channels with the modulating channel spectra.

Abstract: When a subscriber to message retrieval service retrieves a message, rather than reporting a time of day associated with the message that may not have any meaning to the subscriber if the subscriber, the message originator and the message depository are in diverse worldwide locations, the disclosed message retrieval system reports a delta time indicating to the retrieving subscriber the time elapsed since the message originator delivered the message.

Abstract: Metal hydrides are activated by an electrochemical procedure. In this procedure, a bulk sample of the corresponding metal is immersed in an aqueous electrolyte and contacted by a cathode. Current passed through the aqueous electrolyte causes electrolysis of the water and a concomitant reaction with the formation of metal hydride. As a result, the metal hydride is fractured and smaller particles result. Additionally, the resulting metal hydride has a substantial amount of absorbed hydrogen. A novel plating method, taking advantage of the reducing power of hydrogen absorbed in a metal hydride, is useful to encapsulate such metal hydride with a variety of metals. Therefore, such hydrides are uniformly coated by using plating solutions without the standard reducing agent and stabilizer.

Abstract: Electro-static discharge protection for sensitive circuitry in devices, which have exposed metallic contacts for accessing such circuitry, is achieved by providing switching apparatus in these devices. The switching apparatus isolates the sensitive circuitry from static electricity which may be impressed upon the exposed metallic contacts. In operation, when a first device is placed in engagement with a second device for transferring data, charging a battery or the like, the switching apparatus relies on the weight exerted by the first device on the second device for establishing a conducting path between the contacts and the sensitive circuitry in each device. This conducting path is interrupted when the first device is removed from the second device thereby providing isolation for the sensitive circuitry from any static electricity which may be impressed upon the exposed metallic contacts.

Abstract: A data communication system includes a novel transceiver which uses different transmit and receive data symbol lengths enabling the transceiver to operate in a full-duplex mode. The transceiver transmits data of a first type over a communication link during a first time period, and receives data of a second type over the link during a second time period which is longer than the first time period and which overlaps a portion of the first time period. In one embodiment, the transceiver switches a transmitting means to the link during the first time period and connects a receiving means to the link during a portion of the second time period which does not overlap the first time period.

Abstract: Allowing a calling party to enter a message that is transmitted on a destination telephone link during silent intervals of a ringing signal by a switching office. In a first embodiment, the destination telephone link is equipped with the feature of allowing receipt of calling party specified data messages. The switching office automatically accepts information for a data message as dialed digits from the calling party. In a second embodiment, the switching office designates that an originating telephone link can transmit information for a data message. The switching office is responsive to the transmitted information to form a data message and to transmit this data message on a destination telephone link during the silent intervals of the ringing cycles. In a third embodiment, in response to a calling party placing a call to a special telephone number, the switching office requests that the calling party enter a destination telephone number and information for a data message.

Abstract: Applicant has discovered that aliovalently doped zinc-indium-oxide where In is 40-75% of the metal elements can achieve electrical conductivity comparable to wide band-gap semiconductors presently in use while exhibiting enhanced transparency in both the visible and infrared. The material can be doped to resistivity of less than 1 milliohm-cm by small quantifies of aliovalent dopants, such as tetravalent atoms. It can be deposited on glass substrates in amorphous and polycrystalline films.

Abstract: An optical fiber cable has a plurality of loose tubes, each containing at least one optical fiber which is wound to form a loose helical configuration. The loose tubes each contain one or more filamentary members of superabsorbent material. The loose tubes are arrayed around a central organizing member and the assembly is surrounded by a strength member forming a jacket. The strength member is layered with superabsorbent material and the empty spaces within the jacket contain yarn members of superabsorbent material. The entire assembly is surrounded by an outer jacket of suitable material, preferably fire resistant.

Abstract: Method and apparatus for transmitting messages in a two-way paging system are disclosed. Reply codes corresponding to portions of a message to be transmitted by a base station and received by a mobile pager device are computed either at the base station or at the pager according to various embodiments. The reply codes, which are typically shorter and require less bandwidth than the full text to which they correspond, are incorporated by the pager into reply messages when the user of the pager device wishes to refer to portions of the text of the received message in his reply. The present invention advantageously allows the user of a pager device to respond to a received message by transmitting a reply message that incorporates part of the text of the original received message without significantly increasing the bandwidth required to transmit the response.

Abstract: The present invention relates to a waveguide taper. The waveguide taper has a first end and a second end for being coupled with a fiber. The core has an overall width that progressively increases from the waveguide end toward the fiber end such that the width of the fiber end of the taper corresponds to the diameter of the core of the fiber. Side-gaps are disposed in the sides of the core and extend into the core but not across the entire width of the core. The depth of the side-gaps progressively increases from the waveguide end to the fiber end of the taper. In one embodiment, the side-gaps may be aperiodically and/or randomly disposed along the length of the taper and the side-gaps can be disposed at different angles to a direction of light propagation along a length of the core.

Abstract: A method is provided that deters the illicit copying of electronically published documents. It includes publishing a plurality of copies of electronically created material to be distributed to a plurality of subscribers. Each copy of subscriber's document has a unique identification code embedded in the document. The arrangement of the code on the document is based on the line-shifting and word-shifting techniques. This is to minimize the effects from noise and distortions on future illicit copies to simplify detection and decoding of the unique code. A codebook is created to correlate each unique code with each subscriber.

Abstract: A method is provided for reducing the polarization shift between different modes of an optical signal propagating in an optical grating having a plurality of waveguides extending in a common plane. The method includes the step of imparting curvature to the optical grating along a line that traverses the plurality of waveguides in a direction that is substantially perpendicular to the direction in which the optical signal propagates. The curvature varies in a nonuniform manner along the line to which it is imparted. The curvature may vary in a substantially linear manner along this line, which in some cases may define a symmetry axis of the grating. Sufficient curvature may be imparted to substantially eliminate the polarization shift. The curvature may be imparted by flexing the optical grating at two contact points respectively located near a longest and shortest of the plurality of waveguides.

Abstract: A passive fiber optic repeater bypass is provided which brings fault tolerance to repeatered fiber optic transmission systems. A fiber optic bypass provides an alternate signal path around failed repeaters. The bypass optical attenuation is set to ensure the bypass signal is sufficiently small so as not to interfere with the locally regenerated and transmitted signal, but sufficiently large to be received at the next repeater. In the event of a repeater failure, a repeater monitor disables the local laser transmitter allowing the bypass signal to be received at the next repeater.

Abstract: Electromagnetic resonators according to the invention comprise a first body, exemplarily a split thin ring, that is disposed between two planar field confining plates. The thickness (t) of the first body is less (typically less than 1/2 or 1/10) of the outer radius (R) of the body, and the distance between the first body and the confining plates is less than R. In preferred embodiments the first body comprises superconducting material. Resonators according to the invention can be readily assembled into relatively compact filters that are easily tunable, can have large quality factor, and offer the possibility of single mode operation. Such filters can advantageously be used in, e.g., wireless communications systems.

Abstract: A wavelength selective structure is coupled to an adiabatic Y-coupler via a multimode section which supports both symmetric and antisymmetric modes. One single mode branch of the coupler converts guided light to a symmetric mode, whereas the other single mode branch converts guided light to an anti-symmetric mode. The structure, which includes a pair of single mode waveguide arms coupled to the common section and a reflection device (such as a grating or ROR) located in each arm, converts reflected light from a symmetric mode to an anti-symmetric mode and conversely. Applications described include a channel dropping fiber and channel balancing apparatus for WDM systems, and a dispersion compensator for fiber optic systems.