Abstract: A method for determining the endpoint of a plasma etch process is disclosed. The endpoint of the plasma etch process is determined using an acoustic cell attached to an exhaust port on a reaction chamber of a plasma reactor. At least a portion of the gas from the reaction chamber flows into the acoustic cell during the plasma etch process. Acoustic signals are periodically transmitted through the gas flowing in the acoustic cell and a first velocity for the acoustic signals associated with etching a first material layer formed on a substrate is determined. Thereafter, the endpoint of the plasma etch step is determined when the first velocity changes to a second velocity associated with etching the first material layer through its thickness to its interface with an underlying material layer. The gas from the reaction chamber optionally flows through a compressor prior to flowing into the acoustic cell. The compressor increases the pressure of the gas that flows into the acoustic cell.

Abstract: The present invention provides an interlocking connector for a communication card including a first connection portion for connection to signals in the communication card relating to a first device such as a cellular telephone. A second connection portion in the interlocking connector provides for connection to signals in the communication card relating to a second device such as the PSTN. A blocking portion of the interlocking connector prevents electrical connection with the second connection portion and allows electrical connection with the first connection portion when the interlocking connector is connected to the communication card. A communication card is also provided which comprises modem circuitry, and an interface for connection between the modem circuitry and a computing device. A PSTN interface is provided for connection between the modem circuitry and a telephone line, and a cellular telephone interface is provided for connection between the modem circuitry and a cellular telephone.

Abstract: A vacuum collet for handling semiconductor piece parts is formed to include a plurality of separate vacuum ports, disposed in proximity to one another. By selectively turning the vacuum ports "on" and "off", with only one vacuum port turned "on" at a time, a semiconductor chip may be articulated through various 90.degree. rotations to provide the orientation required for placement of the semiconductor chip on a final assembly.

Abstract: A buck switching DC-to-DC regulator having a resistor and capacitor in combination across the storage inductor to measure output current and voltage. The resistor connects to the input of the inductor and the capacitor to the output of the inductor. The junction of the resistor and capacitor connects to an error amplifier for controlling the switching regulator. The regulator may be paralleled for more output current by connecting the outputs together and providing a common reference voltage to all the regulators.

Abstract: Improved curve plotting techniques are disclosed for drawing a substantially smooth curve in real time, from a plurality of sampled points, as the points are sampled, on a point-by-point basis. The curve is substantially smooth in that it has a continuously changing slope of G.sup.1 continuity, as opposed to a slope which changes in a discontinuous or stepwise manner. The curve plotting is performed by representing the x coordinates of the curve using a parametric equation x=?a.sub.x *(t.sup.2)!+?b.sub.x *t!+?c.sub.x !, and by representing the y coordinates of the curve using a second parametric equation y=?a.sub.y *(t.sup.2)!+?b.sub.y *t!+?c.sub.y !, wherein a.sub.x, a.sub.y, b.sub.x, b.sub.y, c.sub.x, and c.sub.y comprise six unknown quantities, and t is a "dummy" valuable. The derivatives of the parametric equations are employed to calculate and to plot the smooth curve.

Abstract: Each user signal of a communications network is encoded using a narrowband traffic code and a wideband cover code for transmission to a signal relay (e.g., a communications satellite) in one of a plurality of uplink signal beams. The signal relay receives all of the user signals in the different uplink signal beams and processes them to re-transmit them in different downlink signal beams to their different appropriate destinations. The narrowband traffic codes and wideband cover codes are selected to encode the individual user signals in such a way as to permit the switching processing of the signal relay to be implemented at the beam level (e.g., individual components processing multiple user signals at a time) rather than at the user level (e.g., one switching circuit for each user).

Abstract: A crucible is disclosed for use in coating a substrate with deposition materials by electron-beam evaporation. The crucible is configured to be inserted into an evaporator pot; it has a bottom and at least one sidewall extending upwardly from the bottom and terminating in a rim, such that the bottom and sidewall define a reservoir for containing the deposition material, and the rim defines a mouth out of which the deposition material may evaporate. A lip extends upwardly from a predetermined section of the rim which shields the spattering of deposition of material onto the evaporator pot during the evaporation process. A improved method is also disclosed for performing electron-beam evaporation with the present invention crucible.

Abstract: A reconfigurable analog-to-digital (A/D) converter that produces an N bit output in a first operating mode and an (N+1) bit output in a second operating mode. The reconfigurable A/D converter is especially well-suited for use in a read channel device.

Abstract: A method and apparatus for discriminating digital data received from a plurality of spatially distinct acoustic sensing nodes of a distributed undersea optical surveillance system. The present invention advantageously employs Code Division Multiplexing (CDM), which is a synchronous variation of Code Division Multiple Access (CDMA), to communicate a plurality of digital data bit-streams from the nodes to a common location remote therefrom. The inventive system generates at the remote location a pseudo-random reference signal that functions as a carrier for communicating sensed acoustic data from the nodes to the remote location. Using the known spatial relationship between the nodes and the remote location and the pseudo-random reference signal, the present invention operatively synchronizes correlators at the remote location to receive and differentiate data from the various individual nodes.

Abstract: An inductor (100) optimized for surface-mount vacuum-pickup automated circuit assembly eliminates the expense of an inductor housing. The inductor has a hollow rectangular ferrite core (101) and a winding defined by a stripline (102) deposited on the core surface. Winding ends are formed by conductive vias (103) in the core that open onto the core surface, where they connect and mount the inductor to a circuit board (150). A flat sheet (104) adhered to one face of the core provides a surface for vacuum pickup and for labeling of the inductor. The core of a passively tuneable inductor (200) defines multiple unconnected winding segments (102-103). Segment ends mount the inductor to the circuit board and connect the segments to circuit board striplines (254) that are laid out in a pattern to interconnect a number of the segments into a winding. The inductor is tuned by changing the stripline layout and thereby varying the number of interconnected segments.

Abstract: A processing system comprising a plurality of processors and a plurality of memories, wherein each processor is connected to a memory by a primary bus. When one processor needs to access another processor's memory, it requests access to that particular memory. A bus control monitors memory transactions and causes the processor for this target memory to relinquish the memory. The bus controller then configures a transfer bus and forwards the memory access command to the target memory such that the processor can then access its target memory in addition to its own memory. This configuration remains stable until any processor requests a memory outside of the current configuration or the processor associated with the target memory requests its own memory again. Advantageously, the bus control uses an arbitration table which provides equitable access to all memories.

Abstract: An optical fiber is disclosed that is suitable for use in wave-division-multiplex (WDM) systems served by Erbium-doped fiber amplifiers. The fiber has a chromatic dispersion whose absolute magnitude is at least 0.8 ps/(nm-km) over the wavelength region 1530-1565 nm, and has a dispersion slope that is less than 0.05 ps/(nm.sup.2 -km). This optical fiber exhibits a loss that is less than about 0.20 dB/km and is relatively insensitive to bending; moreover, its effective area exceeds 50 .mu.m.sup.2. The optical fiber includes a core of transparent material having a maximum refractive index n.sub.1, and a layer of transparent cladding material on the outer surface of said core having a refractive index n.sub.2. The core includes an annular region of transparent material whose minimum refractive index, n.sub.3, is depressed with respect to n.sub.2. These indexes are constrained by the following equations: 0.50<(n.sub.1 -n.sub.2)/n.sub.2 <0.70; and -0.30<(n.sub.3 -n.sub.2)/n.sub.2 <-0.05.

Abstract: In a pulsed Fabry-Perot laser, such as a Q-switched laser or a mode-locked laser, one of the resonator reflectors comprises a waveguide loop coupled to the gain medium via a polarization splitter/combiner. In one embodiment, only a switchable isolator is located in the loop, thereby significantly reducing insertion loss.

Abstract: The present invention is directed to a process for device fabrication in which a pattern is transferred from a photoresist mask into an underlying layer of silicon dioxide. A plasma containing a fluorocarbon gas is used to etch the pattern into the underlying silicon dioxide layer. The plasma is monitored using optical emission spectroscopy to effect control of the etch process. The optical emission is monitored at select wavelengths. To control the process based on an observation of photoresist etch rate, two wavelengths are monitored. One is associated with a species that is produced by the interaction between the photoresist and the plasma, and one is associated with a species related to the plasma intensity.

Abstract: In a pulsed Fabry-Perot laser, such as a Q-switched laser or a mode-locked laser, one of the resonator reflectors comprises a waveguide loop coupled to the gain medium via a circulator. In one embodiment, only a modulator is located in the loop. In another embodiment, the circulator is switchable and the loop may contain either an unidirectional device, such as an isolator, or may contain only the waveguide itself, depending on which states of the circulator are utilized in the switching process. Also described are several arrangements for multiplexing lasers of different operating wavelengths.

Abstract: An asymmetrical half-bridge converter, a method of operating the same and a power supply that incorporates either the converter or the method.

Abstract: For use in a power converter having a rectifier coupled to an output thereof, a snubber circuit including an energy storage device coupled to the rectifier that moderates a voltage across the rectifier and a method of moderating the voltage. In one embodiment, the snubber circuit includes: (1) a first switch that regulates a voltage across the energy storage device, (2) an inductor, coupled to the first switch, that provides a discharge path for energy stored in the energy storage device when the first switch is conducting and (3) a second switch that recovers energy stored in the inductor to the output when the first switch is not conducting. The snubber circuit thereby reduces voltage stress across the rectifier during a current limit mode of operation.

Abstract: A telephone system and method that enables a telephone to handle more call appearances that it has call appearance keys. The telephone system contains a display and general purpose keys that are used to respond to prompts shown on the display. When the telephone system receives an incoming call that is not assigned to a dedicated call appearance key, then the system places a prompt on the display. The prompt identifies the line upon which the telephone call is received by placing an identifying name, number or telephone location on the display. The prompt is placed adjacent to one of the general purpose keys so that the prompt is clearly associated with only one of the general purpose keys. The system then assigns that general purpose key to the telephone line addressed by the prompt. As a result, the general purpose key becomes a call appearance key and a person using the telephone system can complete a connection between that telephone an incoming call by pressing that general purpose key.

Abstract: A circuit for compensating for the input offset voltage of a logarithmic amplifier includes a digital comparator, a logic circuit, and a digital-to-analog converter (DAC) in a feedback loop. The comparator is connected to the output of the log amplifier and digitally indicates the polarity of the input offset voltage when the amplifier input is set to zero. The logic circuit uses the digital output of the comparator to form an adjustable digital compensation signal. This digital compensation signal is applied to the DAC to generate an analog compensation signal that is injected into the input of the logarithmic amplifier to cancel the input offset voltage. The process is repeated until the proper or best compensation signal is produced.

Abstract: An information processing system adapted for use in conjunction with a telephone communication system. The information processing system includes a caller identification signal receiver, a timed switching device, and a call forwarding device. When no incoming call is being received, the timed switching device is in a first, open state, such that a circuit between the telephone line and the call forwarding device is interrupted. Upon receipt of an incoming call on the telephone line, the timed switching device and the caller identification signal receiver are activated. The timed switching device enters a second, closed state after a finite amount of time has elapsed such as, for example, several seconds, thereby allowing sufficient time for the caller identification signal to arrive on the incoming telephone line.