Abstract: In accordance with the invention, the operating frequency of a SAW device is magnetically tuned. In a first embodiment, the SAW device comprises a piezoelectric layer mechanically coupled to a substrate or body of magnetostrictive material. Strains magnetically induced in the magnetostrictive substrate is coupled to the piezoelectric layer, altering the velocity at which it can transmit acoustic waves. In an alternative embodiment, surface waves are directly generated in a magnetostrictive material and the velocity is directly altered by an applied magnetic field.

Abstract: There is disclosed, a converter for converting an input signal from one form to another includes a generator circuit for generating as a thermometer code a plurality of binary signals from the input signal. The converter includes one or more pseudo-majority gate circuits for correcting a broken thermometer code to be a corrected thermometer code. The corrected thermometer code is decoded to provide a digital code corresponding to the input signal. There may be more than one stage of pseudo-majority gate correction.

Abstract: An adaptive high speed data transmission system is described. In one aspect, the transmitter for this system employs a plurality of transmit antennas which have controllable offsets. The transmitter also includes signal coding circuitry suitable for use to address transmission impairments due to fast fading in the transmission channel. At the receiver, the received signal is analyzed to determine the fading characteristics of the channel. Where slow fading is detected, the offsets are employed to convert the slow fading into fast fading. The channel characteristics are continually resampled and these characteristics are used to adjust the transmitter and the receiver to achieve optimal transmission speed.

Abstract: The invention relates to a system for maintaining a log of incoming records for a database system. Seek points are inserted into the compressed data log in a manner that allows recovery to start from a specified point without a need for decompressing earlier portions of the log. The initial block of data is used as the compression dictionary. A new compression sequence using the same initial compression dictionary is started at each seek point.

Abstract: A system and method in which the chromatic dispersion characteristic, as a function of distance along a section of transmissive fiber, is measured. First and second optical signals are launched into a fiber under test to thereby generate, by a four-wave mixing process in the fiber, a probe signal. Because of a wave-vector phase mismatch, the probe signal power oscillates with a spatial frequency that can be measured as a function of distance in the fiber. The intensity oscillations are measurable as, for example, temporal variations in the Rayleigh backscattered light detected at the input end of the fiber. According to the present invention, the dispersion parameter at one or both of the first and second optical signal wavelengths, as a function of length along the fiber, is derived directly from these intensity oscillation measurements. From this information, it is possible to further derive maps at other wavelengths of interest.

Abstract: A method and apparatus use a set of parameters characterizing an interference signal at a base unit for determining power levels for signals transmitted from a communications device to the base unit. The set of parameters comprises second or higher order statistics characterizing the interference signal, and the parameters are used to determine a desired power level for signals received at the base unit. The desired power level is communicated to a communications device via a pilot signal transmitted by the base unit at a predetermined level. The predetermined level and the power of the received pilot signal are used to compute a path gain between the base unit and communications device. The path gain and desired power level are then used to determine the power level of signals transmitted from the communications device to the base unit.

Abstract: The quartz shadow ring of a conventional plasma etching apparatus is desirably coated with material which inhibits the liberation of oxygen into the plasma. Investigation has shown that the liberated oxygen degrades etching uniformity across the wafer.

Abstract: An three-level boost rectifier circuit is described for universal line applications. The boost rectifier circuit includes a boost inductor connected to the input voltage. A bridge rectifier composed of four diodes is connected between the boost inductor and two output capacitors. Two boost switches, each with two series diodes are connected between the bridge diodes and the output capacitors. A threshold switch is connected between the bridge diodes and the output capacitors. The threshold switch is closed when the input voltage is below a predetermined threshold voltage and opened when the input is above the threshold voltage. Closing the threshold switch acts to reverse bias two of the four bridge diodes, reducing the number of diodes conducting at any given moment to one. This reduces the conduction losses of the circuit at low input voltage, making the circuit more efficient at low-line inputs.

Abstract: The invention is a laser with improved turn-on time for digital applications. The low bias capacitance effect of the laser is reduced by use of a buffer region formed between the substrate and the active region, the buffer region having a lower dopant concentration than the substrate.

Abstract: A laser ablation process is described for removing the polymeric buffer layer from glass optical fibers. The ablation takes place within a flow of substantially non-oxidizing gas. In preferred embodiments, the fiber cable is flushed with dry nitrogen and irradiated by a sequence of laser pulses 200-800 .mu.s in width. A currently preferred laser is a carbon-dioxide laser emitting in the infrared portion of the spectrum. The irradiating wavelength is preferably chosen to be 90% absorbed at a depth of 0.5 to 1.0 times the thickness of the buffer layer. The polymeric buffer layer can be removed without previously treating the optical fiber with a chemical softening agent, and without causing any significant reduction in the tensile strength of the fiber.

Abstract: An assembled printed circuit board (PCB) is inspected. The PCB has a device assembled to the PCB by a ball grid array (BGA). The BGA includes a plurality of rows of solder connections. A filament is directed into a first side of the BGA, between two adjacent rows of solder connections in the BGA, as far as it will go. A solder bridge is detected if the filament does not emerge from a second side of the BGA opposite the first side. An inspection apparatus for performing this inspection includes a plurality of filaments. Each filament is longer than a side of the BGA. Each filament has a diameter or thickness sufficiently small to fit between adjacent rows of solder connections in the BGA; and a fixture for holding the plurality of filaments. The fixture has a pitch between adjacent filaments approximately equal to a pitch between adjacent rows of solder connections in the BGA.

Abstract: Embodiments of the invention include a transformer device having a saturation region for limiting ingress noise and other noise. The transformer comprises a magnetic core, an input coil and an output coil arranged so that the output signal caused by the magnetic linkage between the input and output coils through the magnetic core is based on the magnitude of the input signal. According to an embodiment of the invention, the magnetic core includes a saturation region that limits the output signal regardless of the magnitude of the input signal once the saturation region reaches its saturation magnetization state. The saturation region comprises a reduced saturation magnetization level caused by a geometrically constricted region of the magnetic core or, alternatively, by a modified, magnetic-equivalent region having properties similar to a geometrically constricted region.

Abstract: A convolutional encoding apparatus and method for encoding input data with bits stored in a shift register. A predetermined set of coefficient values is provided to define a coefficient mask value. It is then determined whether the bit of the input data is one of a logical zero and a logical one. Only if the bit of the input data is a logical one, the coefficient mask value and the shift register value are combined to produce a next shift register value. Predetermined ones of the bits of the next shift register value are then selected as coded output data.

Abstract: A structure allowing multiple optical paths through an optical isolator or the like with substantially no interaction. A lens collimates light from a first multiple fiber optic path termination. The collimated light is processed by an optical isolator unit or another optical processing unit such as a coupler. The processed light is reimaged onto a second multiple fiber optic path termination. Preferably, the optical paths in the first termination are in one-to-one correspondence with the optical paths in the second termination.

Abstract: The invention is a circuit for monitoring the wavelength of a laser device such as a semiconductor laser. A piezoelectric resonator is positioned in the path of the light beam so as to form a Fabry-Perot cavity. The changes in the reflectivity of the cavity are detected as the resonator is driven by an oscillator circuit, and an error signal is produced in response thereto when the wavelength of the laser device strays from a desired value.

Abstract: A temperature sensing device for permanently indicating when a product is exposed to ambient temperatures exceeding a maximum permitted temperature of the product for a time period long enough to permanently damage the product. In an exemplary embodiment, the temperature sensing device is typically located on the protective cover of a battery away from terminals and the battery casing. The temperature sensing device is made of a material to permanently expand and/or shrink upon reaching critical temperatures (e.g. too hot). The expansion is visually detectable by means of a visual indicator and/or reference point.

Abstract: A method for fabricating a multi-level integrated circuit is disclosed which utilizes a grid pattern from which portions corresponding to the metal layer are selectively removed to form a mask which is subsequently used to deposit dummy features in the open areas between metal lines, thereby to allow the deposition of a substantially planar dielectric surface over the metal layers and dummy features.

Abstract: A telecommunication network includes the first subscriber served by one type of telecommunication switch and a second subscriber served by a different type of telecommunication switch. A group affiliation parameter which defines an organization of which the first subscriber is a member is included in a call setup message. Upon receiving the call setup message at a telecommunication switch associated with a called second subscriber, a determination is made of whether the first and second subscribers are members of the same organization. Upon determining that the first and second subscribers are members of the same organization, call handling parameters associated with the first organization are used to process the call request to allow common control of such calls even though the first and second subscribers are associated with different types of telecommunications equipment.

Abstract: Speech recognition technology has attained maturity such that the most likely speech recognition result has been reached and is available before an energy based termination of speech has been made. The present invention innovatively uses the rapidly available speech recognition results to provide intelligent barge-in for voice-response systems, to count words to output sub-sequences to provide paralleling and/or pipelining of tasks related to the entire word sequence, and to count words to provide rapid, speech recognition based termination of speech processing and outputting of the recognized word sequence.