Abstract: The specification describes a lift-off technique useful in the manufacture of III-V semiconductor devices such as MQW lasers. The lift-off step is improved by a spacer layer of III-V semiconductor that can be non-selectively etched to form a mesa stripe, and selectively etched for the lift-off step. The spacer layer allows the etch mask to be dimensionally adjusted to reduce or eliminate overhang of the mesa, and prevent adverse shadowing effects. MBE is effective for both growing the multilayer stack and regrowing the blocking layer. A self-aligned mask on the multilayer stack can be produced by removing the overhang, and facilitating lift-off by producing an undercut in the III-V spacer layer using selective etching.

Abstract: For use in a power supply having a bias circuit with a bias transformer, an auxiliary bias circuit and a method of providing power via the auxiliary bias circuit to an auxiliary load. In one embodiment, the auxiliary bias circuit includes a blocking device coupled to the bias transformer. The auxiliary bias circuit also includes a storage device, coupled to the blocking device and across the bias transformer, that provides a voltage to drive the auxiliary load without requiring a separate power supply.

Abstract: A method and apparatus for generating two disparate frequency reference signals using a single phase locked loop. The circuit includes a local oscillator for generating a reference signal and a phase comparator for comparing the reference signal with a feedback signal. The output of the phase comparator is converted to a first one of the desired output frequencies by a voltage controlled oscillator. That signal is also fed to a variable frequency divider circuit under control of a &Sgr;/&Dgr; converter which generates a lower frequency signal without creating a secondary frequency tone. The lower frequency signal is the second of the output frequencies. This signal also is fed back to the second input of the phase comparator through a fixed frequency divider.

Abstract: A system is disclosed for displaying information pertaining to the usage of Web pages. The system comprises first and second Web sites. The first Web site comprises plural Web-component files, each having a name in a Web-site directory. The second Web site comprises plural statistics files, each containing usage information about a corresponding Web-component file or sub-directory of Web-component files. The system further comprises a computing device that has a display screen, is operable by a user, and is in communication with the first and second Web sites. The computing device is operated under the control of Web-browser software effective for displaying, on the screen, Web components of the respective Web sites.

Abstract: An electronics package consisting of a molded plastic body on a ceramic substrate is provided with a layer of a ceramic surrogate material on a surface of the plastic body opposite the ceramic substrate to reduce bending stress of the package. The coefficient of thermal expansion of the ceramic surrogate layer is less than that of the ceramic substrate. Equations are developed for determining an optimum thickness for the surrogate layer.

Abstract: A system for debugging the computer program present in read-only memory (ROM) contains a debugger, a processor, read-only memory, a bus and a hardware debugging support module. The hardware debugging support module contains a first register called the range start register, a second register called the range end register and a comparator. The debugger uses a list of “n” user specified break points to divide a computer program into “n+1” regions, each of which has a start address and an end address. The first register and the second register of the hardware debugging support module are programmed with the start address and end address of a region which contains a specific address. The comparator is connected to the first register and second register of the hardware debugging support module and is also connected to the bus which connects the read-only memory to the processor.

Abstract: A probe tip locator for use in determining the x-axis location and y-axis location of a probe tip of a microscope relative to the locator, the locator comprising a plurality of first reference lines parallel in a first direction, each of the first reference lines representing a predetermined x-axis location of the probe tip; a plurality of sets of parallel encoded bit fields, each one of the sets corresponding to one of the first reference lines; and a plurality of second reference lines parallel in a second direction, each one of the second reference lines intersecting at least one of the first reference lines at an acute angle, such that a scan of a portion of the locator is used to determine the x-axis location and y-axis location of the probe tip relative to the probe tip locator by movement of the probe tip relative to the probe tip locator.

Abstract: A method for making a semiconductor device includes the steps of forming a first conductive layer adjacent a substrate, forming an etch stop layer on the conductive layer, and forming a dielectric layer on the etch stop layer. The dielectric layer includes a material having a low dielectric constant, and a via is formed through the dielectric layer to expose the etch stop layer at the bottom, with porous sidewalls being produced. The exposed etch stop layer is etched using an etchant that cooperates with etched material from the etch stop layer to form a polymeric layer to coat the porous sidewalls of the via. Since the etchant cooperates with the etched material from the etch stop layer to form the polymeric layer coating the porous sidewalls of the via, a separate coating layer deposition step is not required after the via is etched and cleaned.

Abstract: A laser bias preconditioning methodology is provided, and an implementation of that methodology, that improves the carrier-to-noise ratio of analog CATV signals sent over an optical transmission medium. The bias preconditioning methodology causes the laser bias current to be continuously varied to track an envelope of the carrier signal.

Abstract: Methods and apparatus for performing non-linear analysis using preconditioners to reduce the computation and storage requirements associated with processing a system of equations. A circuit, system or other device to be analyzed includes n unknown waveforms, each characterized by N coefficients in the system of equations. A Jacobian matrix representative of the system of equations is generated. The Jacobian matrix may be in the form of an n×n sparse matrix of dense N×N blocks, such that each block is of size N2. In an illustrative embodiment, a low displacement rank preconditioner is applied to the Jacobian matrix in order to provide a preconditioned linear system. The preconditioner may be in the form of an n×n sparse matrix which includes compressed blocks which can be represented by substantially less than N2 elements.

Abstract: A magnetic recording control circuit for controlling current through a magnetic recording head includes a switch network, a signal coupler, and first and second voltage clamps. The switch network is connected to first and second magnetic recording head node regions and includes first, second, third, and fourth switches each having a variable magnitude conduction path and a control region. The signal coupler includes an input region and a plurality of output regions each connected to the control region of a corresponding switch. The first and second voltage clamps limit voltage differences between the magnetic recording head node regions and the control regions of the first and second switches.

Abstract: The present claimed invention improves on the conventional comb and multiple router approach by making multiple use of a single router by using interleaved groups of wavelengths that enter through different entrance ports and exit through different groups of exit ports of the same router. This permits better separation (lower crosstalk) between adjacent channels, greatly reduced temperature sensitivity, small physical size and lower cost. With these improvements, a large number of wavelength add/drop sites may be cascaded in WAD/WDM systems.

Abstract: Improved telecommunication apparatus is realized with a structure that is tailored to provide an ID signal to the telecommunication network, which signal uniquely identifies the apparatus. The ID signal can be communicated to the network under control of the apparatus, or polled by the network. The apparatus includes a second port through which communication services are provided to a customer, and the ID signal can be sent to that second port as well. The apparatus further includes circuitry for processing signals flowing between the two ports, allowing the characteristics of the signal to change and thereby provide for format conversions, encryption, and other capabilities.

Abstract: A telephone calling card (prepaid or postpaid) service system with an intelligent network (IN) for automated call processing has a bailout capability for bailing out a call placed directly to the IN, to an operator for assistance upon the occurrence of predefined contingencies. A service control point (SCP) in the IN interfaces with a switch containing a service switching point (SSP) for switching a call to its destination via the ETSI INAP or ITU INAP protocol. The switch also contains an operator service position system (OSPS), and an originating call processor (OCP) coupled to both the SSP and OSPS. After the occurrence of a bailout condition (resulting from a call being unauthorized as determined by the SCP), the SCP sends a destination routing address to the SSP including a network routing address (NRA) indicating which OSPS to direct the call for eventual operator assistance (via the SSP).

Abstract: A verification of the protocol between the various communicating elements of a concurrent system may be performed directly using the actual code that implements the element when it is actually operating. This is achieved by combining stateless search techniques with partial order methods, namely, persistent set and sleep set methods. In particular, the code of each element of a system is exercised by a scheduler in such a way that global states of the system are visited according to a stateless search, which is a search that does not use an explicit representation of the global states. A global state is a state in which the next operation to be executed by every element of the system is a visible operation. The set of visible operations includes at least those operations related to communication between the elements.

Abstract: A micromechanical tilt mirror device that includes a membrane suspended by its ends over a substrate such that a mirror area of the membrane is asymmetrically positioned on the membrane whereby it is tilted when the membrane is deformed by electrostatic forces. This mirror tilt is used to steer an incident light beam in a prescribed direction. The mirror can be supported to provide tilt in either of two orthogonal directions with respect to a rest direction.

Abstract: A memory addressing scheme suitable for use for either interleaving or de-interleaving data bytes of, e.g., a broadcast digital television (DTV) data stream. A number of memory branches are configured in a random access memory (RAM), wherein at least some of the branches have different numbers of memory locations for reading out and for storing data bytes, thus defining memory branches of different lengths in the RAM. A start address is determined for each of the memory branches in the RAM, corresponding to a first memory location of each branch. An offset value is determined for each memory branch, to be added to the start address for the branch for addressing a memory location of the branch. If an offset value does not exceed the length of a corresponding branch, an address corresponding to the sum of the branch start address and the offset value is generated for addressing a successive memory location of the branch, and the offset value for the branch is incremented by one.

Abstract: An arrangement for a teleconferencing bridge allows one or more users to control at least one characteristic of at least some of the input signals received by the bridge, such that the output signals received by each user in a teleconference is a user-controlled combination of all the input signals, including the changed input signals. The arrangement allows a rich set of audio bridging features to be provided cost-effectively. Those features include subconferencing, monitoring, whispering, muting, complex gain control, and pseudo stereo.

Abstract: For use in a power converter having an inverter coupled to an output rectifier, a post-regulator, a method of operating the same and a power converter incorporating the post-regulator or the method. In one embodiment: (1) a switching circuit, having at least one controllable switch and coupled an output of the power converter, that receives an output voltage from the power converter and produces a phase-shifted waveform therefrom and (2) a transformer, having a primary winding coupled to the switching circuit and a secondary winding coupled to the rectifier, that delivers the phase-shifted waveform to the rectifier to regulate the power converter, thereby allowing the inverter to be unregulated.

Abstract: A system provides short range wireless data communication from a central control point (e.g., interrogator) to inexpensive endpoints (e.g., tags). The endpoints utilize the technology of modulated backscatter for transmission from the tags to the interrogator. The system uses a new downlink protocol for data transmission from the interrogator to the tags and a new uplink protocol for data transmission from the tags to the interrogator. Both protocols use a backoff/retry algorithm to randomly retransmit any non-acknowledged messages. System capacity from the tags to the interrogator is further enhanced by the use of uplink subcarrier frequency division multiplexing.