Abstract: The present invention is predicated upon the discovery by applicants of a relationship describing thermal decay of radiation-induced index changes and a mechanism which permits stabilization by accelerated aging. Specifically, the induced index change decays in proportion to 1/(1+At.sup..alpha.) where A and .alpha. are functions of temperature, and the decay can be accelerated by heat treatment. As a consequence, the extent of decay can be determined for arbitrary time and temperature and, significantly, an appropriate heat treatment can be scheduled for making a device stable within predeterminable limits.

Abstract: This tone detector which is suited for dual tone multifrequency (DTMF) digit detection, separates the pairs of tones into a low frequency and high frequency group in which the other frequency group is attenuated by filtering. The amplitude of the low and high frequency groups serve as separate variable threshold reference signals. Individual tones are bandpass filtered with their corresponding outputs converted into an amplitude signal. The amplitude of the individually bandpass filtered tone signals are compared against the corresponding low or high frequency variable threshold signal for a determination of whether a tone is present. Preferably, additional validation steps are applied to the preliminary tone decisions to provide improved digit detection accuracy, especially in the presence of other signals such as speech.

Abstract: In a conventional overmolded leadframe package, having a multiplicity of leadframe fingers and encasing one or more electronic devices, a window is formed. The window exposes at least three selected ones of the leadframe fingers at localized sites. At these (exposed) sites of these selected ones of the leadframe fingers, these fingers are coated with a contact material such as gold, whereby localized contact sites are formed. Electrical conductors emanating from one or more external devices--such as electronic devices, electro-optic devices, or opto-electronic devices--can then be bonded to these localized contact sites. The remaining (non-selected) leadframe fingers are typically bonded to a wiring board.

Abstract: Disclosed is a connector module which protects adjacent contacts from being shorted by condensation. Ridges are provided on a housing adjacent each contact such that water droplets of a sufficient width to bridge the distances between contacts cannot form.

Abstract: A technique for efficiently utilizing memory in determining a next state accumulated cost in a communications system or a Viterbi decoder. The system includes a memory having an array of registers. A first present state accumulated cost is retrieved from a first storage register of the array. A second present state accumulated cost is retrieved from a second storage register of the array. A first next state accumulated cost is calculated based on the first present state accumulated cost. The first next state accumulated cost is stored in the first storage register of the array. An advantage of the invention is that such a technique requires less memory to calculate and store accumulated costs. The number of memory locations required is one for each individual state, which is substantially half of the memory locations required previously.

Abstract: A method and apparatus for non-destructively measuring dispersion-zero wavelengths along an optical fiber makes use of a four-photon-mixing technique to generate mixed, amplified, idler signals at positions or ranges along the fiber. The dispersion zero wavelengths are then calculated using the wavelengths of the generated idler signals after taking into account inaccuracies due to higher order phenomena.

Abstract: Efficient digital compression of 3D/stereoscopic video is achieved by a novel technique in which various views forming 3D/stereoscopic video are coded by utilizing the redundancies among the views. Coding is performed in a manner compatible with existing equipment to allowing decoding of one layer of video for display on normal (i.e., monoscopic) displays. The motion compensated discrete cosine transform ("DCT") coding framework of existing standards such as the Motion Pictures Expert Group-Phase 2 ("MPEG-2") video standard is exploited, and when necessary extended, to result in highly efficient, yet practical, coding schemes.

Abstract: Briefly in accordance with one aspect of the present invention, a voltage-to-current converter for converting an input voltage signal to an output current signal, exhibits a substantially linear voltage/current characteristics over the entire available voltage signal range. The voltage-to-current converter comprises a first voltage-to-current converter having a substantially linear voltage/current characteristic for input voltage signals smaller than a first reference voltage signal level and up to substantially the minimum voltage signal level generated by a DC power supply employed to drive the voltage-to-current converter. A second voltage-to-current converter has a substantially linear voltage/current characteristic for voltage input signals larger than a second reference voltage signal level and up to substantially the maximum voltage signal level generated by the DC power supply.

Abstract: The present invention provides a method for metallizing a ceramic surface comprising a ferrite through a surface reduction treatment. A ceramic surface comprising a ferrite is heated. At least a portion of the ferrite is contacted with a gaseous reducing agent to create a metallic region by removing oxygen from the ferrite. The surface is cooled and, optionally, post-treated to enhance adhesion of the metallic region. Typical gaseous reducing agents are hydrogen, forming gas, and ammonia while typical ferrites are nickel-zinc ferrites and manganese-zinc ferrites. To form patterned regions, portions of the substrate are masked or portions of the reduced layer are removed.

Abstract: A Mnemonic Number Dialing Plan is offered, having a telephone keyset which can be used in regions where the written language is based on a large number of characters or symbols. Selected phonetic characters of the known phonic character set are identified with the various numerical keys of the keypad in a relatively flexible association allowing adaptability to a number of different phonic character sets of varying size. The mnemonic to be translated into a telephone number preferably consists of a phrase, where the number of words corresponds with the number of digits in the telephone number, and only the first phonic sound of a word in the mnemonic phrase is used in mnemonic dialing.

Abstract: Techniques for reducing the amount of junk e-mail received by a user of an e-mail system. A recipient description containing non-address information is added to an e-mail message. The user has an e-mail filter which has access to information which provides a model of the user. The e-mail filter uses the non-address information and the model information to determine whether the e-mail message should be provided to the user. The e-mail filter further has access to information which provides models of the user's correspondents. If the filter does not provide the message to the user, it uses the non-address information and the model information of the user's correspondents to determine who the message might be forwarded to. A sender of e-mail can also use the model information of the sender's correspondents together with the non-address information to determine who the message should be sent to. The techniques are used in a system for locating expertise.

Abstract: There is disclosed an integrated circuit that includes a digital-to-analog converter having a resistor string driven by a current source. The resistor string is coupled to the current source. Intermediate taps are defined at the resistor junctions as well the resistor-current source junctions. Switching transistors are coupled between an output node and a respective intermediate tap. A selection circuit is coupled to a terminal of each switching transistor for selectively switching the transistors to a predetermined state to electrically couple the associated intermediate tap to the output node.

Abstract: An optical terminator 100 is designed to make end-to-end contact with an optical fiber 31 whose end portion is held within a cylindrical ferrule 400. The optical terminator minimizes reflections that occur when an optical path encounters an abrupt change in refractive index (e.g., when the end face of the optical fiber encounters an air gap). The optical terminator comprises a solid cylindrical structure, molded from a polymeric material (e.g., a methylpentene copolymer) having a refractive index similar to that of the optical fiber. The proximal end of the terminator abuts the cylindrical ferrule and is solid for a predetermined distance `d` along its longitudinal axis in order to provide at least 20 dB attenuation. The polymeric material is moldable and exhibits minimum indentation creep under a compressive load at elevated temperatures. In one embodiment, the terminator 100 is installed in a plug configuration.

Abstract: Electronic devices having at least two components with mating contact pads are provided with high-aspect-ratio solder joints between the mating pads. These joints ar formed by placing a composite solder medium containing solder wires in an electrically insulating matrix such that at least two solder wires are in contact with the mating pads, and fusing the wires to the pads. The insulating matrix with remainder of solder wires is then optionally removed from between the said at least two components. The composite solder medium is formed by preparing an elongated body of solder wires in an insulating matrix and cutting off slices of the composite solder medium, the solder wires having a high-aspect-ratio of length to their diameter. Alternatively sheets of the composite solder medium are prepared by magnetically aligning solder coated magnetic particles into columns arranged transverse of an insulating matrix and heating sufficiently to fuse the solder in each column into a continuously conducting solder path.

Abstract: A socket connector having improved protection against electrostatic discharges. The body of the connector is encircled by a conductive shell and contains a plurality of female contacts for receiving respective pins of a pin connector. The surface of the body facing the pin connector is coated with conductive material which is coupled to the conductive shell through a conductive stripe on the body and a resilient conductive member contacting both the stripe and the shell. Charge reaching the conductive material from the pin connector is led harmlessly to ground from the shell.

Abstract: An apparatus and method for electronically producing music includes an adder coupled to a sinusoid memory, wherein the sinusoid memory is a look-up table including various sinusoidal waves having differing output characteristics. A feedback path between the output of the sinusoid memory and an input of the adder includes a register coupled to a feedback modifier device. The feedback modifier device includes a second look-up table which substitutes a feedback component .beta. into the sinusoidal wave output from the sinusoid memory. The output of the feedback modifier device is an arbitrary function of the selected wave from said sinusoid memory and the selected value of the feedback component.

Abstract: An integrated circuit device with a light-emitting diode thereon is disclosed. The device has discrete regions which function in concert to emit light when a suitable amount of voltage is provided. The device has four discrete regions: a first doped silicon region; a second silicon dioxide region; a third organic material region; and a fourth conducting material region. The first and fourth regions are electrodes which inject holes and electrons into the conducting organic material. The second region lowers the energy barrier between the first and third regions which improves the efficiency with which the polymer emits light. The diode of the present invention is fabricated on an integrated circuit using conventional integrated circuit fabrication techniques.

Abstract: A magnetic device, a method of manufacturing the magnetic device and a DC/DC converter employing the magnetic device.

Abstract: The number of circuit path crossover points on boards mounting plural connected multichip modules is substantially reduced over the number that would otherwise be required. For 4-sided modules and boards, the modules are arranged on the board in such a way that their inter-connecting north-east-south-west ports are successively reordered to N-S-E-W. Additionally, further advantage in reducing crossover vias may be gained by combining the reordering with a phased rotation of the modules from their nominal congruent board position. For the 4-sided module, these expedients virtually eliminate crossover vias between the east and west ports. It also provides for all MCMs a ready common bus structure located at a common interior area of the mounting board, to which the E- and W-ports are oriented. The invention is applicable to a class of multi-sided, multi-chip modules on boards with a like number of sides.

Abstract: The present invention in one embodiment provides a distortion creation and reduction circuit comprising a distortion circuit, a correction circuit, and a final signal combiner. The distortion circuit receives a first carrier signal and forms a first distorted carrier signal comprised of a first carrier signal and a first distortion signal component. The correction circuit receives a second carrier signal and forms a second distorted carrier signal comprised of a second carrier signal and a second distortion signal component. The first and second distorted carrier signals are formed and combined so that the first and second distortion signal components destructively combine and the first and second carrier signal components constructively combine. The distortion circuit is preferably comprised of a power amplifier. The correction circuit preferably comprises a distortion correction portion, a carrier correction portion, a correction signal combiner, and a correction amplifier.