Abstract: An improved, single diaphragm SOD microphone uses acoustic filters to remove resonances associated with the ducting that guides the ambient sound pressure to the front and rear faces of a FOD microphone element. The microphone element communicates with respective front and rear chambers, two ports communicate with the front chamber via front conduits, and two ports communicate with the rear chamber via rear conduits. The microphone further comprises first and second side chambers for dissipating acoustic energy of undesired resonances. The first side chamber communicates with the front conduits, and the second side chamber communicates with the rear conduits. In specific embodiments of the invention, each of the side chambers comprises a branch conduit approximately equal in length to one-quarter wavelength of an undesired resonance. In certain embodiments, each of these branch conduits includes a small neck joining the branch conduit to its corresponding front or rear conduits.

Abstract: Dielectric layers comprising a silicon oxide and having essentially constant thickness across a wafer are produced by a plasma-deposition method; in preferred processing, a wafer is supported on a surface which extends significantly past the edge of the wafer. Resulting layers may be further processed by localized etching of windows or vias, uniform layer thickness being particularly beneficial, when timed etching is used, to ensure uniformity of etched openings.

Abstract: This invention relates to a novel design for a low-loss optical power splitter, in particular Y-branch types resulting from chemical vapor deposition (CVD) fabricated silica waveguides. More specifically, the present invention utilizes mode matching of the fundamental modes between the input and the output waveguides of a splitter to optimize the splitters operational performance. The optical power splitter of the present invention comprising an input waveguide region having a predetermined width (W) and capable of transmitting optical energy having a fundamental mode E.sub.1.sup.0. Additionally, the splitter includes at least two output waveguide regions positioned to receive at least a portion the optical energy from the input waveguide region wherein the output waveguide regions each have predetermined widths (w) and are capable of transmitting optical energy having a fundamental mode E.sub.2.sup.

Abstract: An improved call-coverage arrangement (106) allows a principal (120) to program (administer) and name multiple independent call-coverage paths (211) for the principal's telephone number. Selection of an individual call-coverage path for an individual call to the principal's telephone number depends either on which one of the call-coverage path is active (221) or on which one of the call-coverage path's selection criteria (212) are matched by the parameters of the call. The selection criteria are likewise programmable by the principal. The principal remembers and accesses (for administration) individual call-coverage paths by name (220).

Abstract: A device for providing a balanced input over a photoelectric cell used in a motion picture film projector and for providing an unbalanced output audio signal for driving subsequent elements in an audio reproduction unit connected to the motion picture film projector, wherein the reproduced output audio signal has an improved quality over that of a previously known transformer output signal. The circuit supplies an unbalanced voltage signal in response to a current generated by a photoelectric cell having at least a first and second terminal. The circuit includes: a current to voltage converter for receiving the current from the first terminal of the photoelectric cell and providing a first output voltage and a current return unit connected to the current to voltage converter for receiving the first output voltage and for providing a second output voltage and for providing a return current along the second terminal of the photoelectric cell.

Abstract: An optical coupling prevents light from entering free space when disengaged. The optical coupling includes a receptacle and a connector plug. The receptacle has an opening and includes an optical radiation source, and a beam stop. The optical radiation engages the beam stop when the receptacle is disengaged from the connector plug. When the connector plug is engaged into the receptacle opening, optical radiation from the receptacle is emitted on the radiation receptor.

Abstract: A pipelined adaptive infinite impulse response (PAIIR) filter is disclosed including an adaptive section and a non-adaptive section, where the PAIIR filter is responsive to first and second input signals. The PAIIR filter includes a plurality of delays and a first polynomial signal generator. The plurality of delays are adapted to re-time a first polynomial value signal, the second input signal, and an error signal. The first polynomial signal generator is adapted to perform relaxed look-ahead processing on the second input signal in the adaptive section. The first polynomial signal generator is responsive to the re-timed error signal so as to generate and adaptively update a first set of weight signals corresponding to first polynomial weights and so as to generate the first polynomial value signal therefrom.

Abstract: Analog and mixed signal integrated circuits are tested using the modified Volterra series to model the integrated circuit being tested. An adaptive algorithm, for example, least mean square or Kalman, is used to determine to coefficients of the Volterra series. The coefficients are then used to calculate the THD and SNR.

Abstract: The novel unipolar laser resembles a quantum cascade laser but utilizes radiative transitions between upper and lower minibands of superlattices, with injection of charge carriers from the lower miniband into the upper miniband of the adjacent downstream superlattice facilitated by a multilayer injector region. The lasing wavelength is typically in the mid-infrared, selectable by choice of the superlattice parameters. The novel laser is potentially well suited for high power operation, since it utilizes carrier transport in minibands, as opposed to tunneling between discrete energy states.

Abstract: A compact waveguide grating router is constructed by forming at least first and second free space regions, first and second sets of optical ports, and a grating array, onto a substrate. The grating array is coupled to the first free space region and the second free space region. A first plane defining a first reflective surface is introduced into the first free space region, and a second plane defining a second reflective surface is introduced into the second free space region. The first plane is oriented such that incident optical signals from the first set of optical ports are reflected to the grating array, and the second plane is oriented such that incident optical signals from the grating array are reflected to the second set of optical ports. The first and second planes are provided, for example, by cleaving, cutting, etching, sawing, or any other suitable technique. The first and second planes enable the input and output ports to be folded back into previously unoccupied space.

Abstract: The method of making an optical fiber refractive index grating comprises writing the grating through the fiber coating. The method involves providing optical fiber of significantly higher photosensitivity than conventional fiber, such that the grating can be written before unacceptable darkening of the coating occurs. Such fiber is H.sub.2 and/or D.sub.2 -loaded silica-based fiber having a Ge-doped core, the fiber selected to have a germanium-oxygen deficiency center content that provides the fiber with a photosensitivity that is at least twice as large as that of an otherwise identical, conventionally prepared, optical fiber. The fiber typically is drawn from a preform, at least a portion of which was exposed to a reducing atmosphere at an elevated temperature.

Abstract: An optical signal attenuation device and associated method for selectively attenuating the signal strengths of different wavelength signals contained within a multiplexed optical transmission. The attenuation device includes a diffracting element that diffracts the multiplexed optical system and directs the different wavelength signals onto separate optical paths. A modulator array is provided that contains a plurality of optical modulators spaced at a pitch so that each modulator receives one of the different wavelength signals. Each optical modulator causes a signal to be produced that correspond to the signal it receives, except that the signal strength of the emitted signal is altered to fall within a desired range. Each signal emitted by the optical modulators is again directed toward a diffraction element. The diffraction element combines the separate wavelength signals, thereby producing a multiplexed signal where each wavelength has a signal strength that falls within a common range.

Abstract: Disclosed is a channelized multi-carrier signal processor capable of equalizing power levels of individual carriers of a multi-carrier signal to within a predetermined dynamic range. In one embodiment, the signal processor includes a power splitter for splitting a multi-carrier input signal into a plurality of electrical paths. In each electrical path there resides a signal modifier that is operable to isolate signal energy associated with a given carrier of the multi-carrier signal. Each signal modifier includes an automatic gain control (AGC) circuit to control the power level of the carrier isolated therein to within a predetermined power level window so that the isolated carriers of each signal modifier are equalized in power. A power combiner then combines the equalized carriers to produce a multi-carrier output signal, which can be applied to a limited dynamic range device such as an A/D converter.

Abstract: A private base station supports the registering of multiple mobile stations and provides a personalized call delivery feature for each registered mobile station. Each mobile station registers separately with the base station when within communication range of the base station. When registration of a mobile station with a private base station is performed, the private base station communicates mobile station information to a base station location register along with assignment of a local unique address for each one of the multiple mobile stations registering with the private base station. When the private base station receives an incoming call for a particular one of the mobile stations, this local unique address associated with the particular station is provided by the base station location register as part of the incoming call information also received by the base station thereby allowing the base station to distinctively alert the particular mobile station.

Abstract: Disclosed is a security mechanism for electronics enclosures such as network interface units which permits access by customers and craftspersons. A bracket is mounted to the cover of the enclosure. The bracket includes two apertures, one for receiving a security screw, and the other for receiving an ordinary screw which fastens the cover to the enclosure. The bracket also includes a cavity which accommodates the shackle of a padlock so that the ordinary screw can be covered and access prevented. Craftspersons can override the padlock by loosening the security screw and moving the bracket until the padlock is removed from the cavity.

Abstract: Polymers suitable for chemically amplified resists based on styrene chemistry are advantageously formed with a meta substituent on the phenyl ring of the styrene moiety. Additionally, polymers for such applications including, but not limited to, meta substituted polymers are advantageously formed by reacting a first monomer having a first protective group with a second monomer having a second protective group. After polymerization, the second protective group is removed without substantially affecting the first protective group. For example, if the first protective group is an alkoxy carbonyl group, and the second protective group is a silyl ether group, treatment with a lower alcohol with trace amounts of acid transforms the silyl group into an OH-moiety without affecting the alkoxy carbonyl group.

Abstract: A method of electrically and mechanically bonding conductive surfaces with conductive adhesives, wherein at least one of the conductive surfaces is of the type upon which unstable oxides readily form. The conductive adhesives having a predetermined amount of conductive particles. The conductive particles having a rigidity at least as hard as the materials composing the conductive surfaces and any oxide formed thereon. The bonding method including the step of preparing the conductive surfaces so that a microscopically roughened oxide surface is formed thereon. The method further including the step of simultaneously applying a predetermined amount of heat and pressure to cure the conductive surface-conductive adhesive-conductive surface joint such that the conductive particles in the conductive adhesive pierce through the oxide to make direct contact with the conductive surfaces thereunder. The method controls the mechanical strength of the bond and the electrical characteristics of the bond joint.

Abstract: A drive circuit for a converter and a method of driving a converter. The converter includes an inverter and a synchronous rectifier. The drive circuit includes: (1) a modulation circuit for generating a drive waveform for controlling the inverter and the synchronous rectifier employing a negative feedback loop, (2) a modification circuit, coupled to the modulation circuit, for sensing an operating condition of the converter and shifting a portion of the drive waveform as a function of the operating condition, the modification circuit thereby creating a variable drive waveform from the drive waveform without employing negative feedback and (3) a transmission circuit, coupled to the modification circuit, for applying the variable drive waveform to the converter, thereby allowing a variable nonconcurrent change in state of the inverter and the synchronous rectifier according to the function of the operating condition.

Abstract: Techniques for displaying an intermediate level of detail in a computer system. The techniques are employed in a system for discovering information about a large body of software. The system displays representations of up to 40,000 lines of code in a single window. Included in the techniques for displaying the intermediate level of detail are the use of color and shape to indicate characteristics of lines, the linking of all of the lines which share a certain characteristic, and selection at the levels of the line, the characteristic, and the file. The software information system further includes one or more code viewers for simultaneously displaying selected lines of code. A cursor may be attached to or detached from a single one of the code viewers.