Abstract: A ferroelectric dielectric for microwave applications is provided comprising a polycrystalline perovskite phase of lead zirconate titanate dielectric material. Small grain size material is provided by a low temperature process, by a rapid thermal annealing process. A layer of amorphous ferroelectric precursor material is deposited and annealed in an oxygen containing atmosphere in the presence of water vapor, preferably with the addition of a few percent of ozone, and at a temperature of less than 500.degree. C. Advantageously, the method provides for formation of a ferroelectric material comprising lead zirconate titanate with a grain size less than 20 nm, with low film stress, high dielectric constant and low leakage current, which has excellent ferroelectric characteristics up to 10 GHz. This material has applications for capacitors, as filters, decoupling, coupling, and bypass elements and also for high frequency surface acoustic wave devices.

Abstract: It is common that the presence of a defect causes abnormal gate output voltage excursions in data buffers, AND gates, OR gates and multiplexers in current-mode logic circuits. A voltage excursion is detected by a voltage excursion detection apparatus which includes a built-in detector. The detector, which is little overhead, is used to monitor output swings of all gates (differential circuits) and flags all abnormal voltage excursions. These detection results cover classes of faults that cannot be tested by stuck-at testing methods only. The voltage detection apparatus works well below "at-speed" frequencies.

Abstract: A transmission line impedance matching apparatus is disclosed that limits longitudinal signals and matches the longitudinal characteristic impedance between two conductors and comprises a common mode choke and an impedance matching device. The common mode choke, comprising two windings wound in the same direction, acts as a high impedance to longitudinal high frequency signals. As a result of this, standing waves are caused by the metallic signals reflecting off the choke. The impedance matching device, comprising two windings wound in the same direction, provides a good match to the longitudinal characteristic impedance and thus reduces standing longitudinal waves and reflections. The apparatus may include a terminal corrector or a mid-line corrector, or a combination thereof. This invention may allow greater bandwidth to be dedicated to services and allow transmission over longer subscriber loops before the minimum S/N ratio is achieved.

Abstract: A multi-ratio frequency divider, which is implemented in a BiCMOS (bipolar-complementary metal oxide semiconductor) circuit, includes a dual-modulus counter for dividing by P+1 and P. P+1 is a power of two and there is not necessary an additional flip-flop responsive to high input frequency, which consumes power due to bipolar transistor devices. An output from the counter is further divided by a variably set value. When its count reaches another set value, the division ratio of the dual-modulus counter is switched to another division ratio. When the further divided counter reaches the variably set value, a new cycle starts. The total division ratio of the multi-modulus frequency divider is a combination of the variably set division values, both being binary bit data. No decoder is necessary for converting an input division ratio to the set values.

Abstract: A polymeric telephone base having two housing members with one of the members provided with an integral mounting for receiving a telephone operating component. A plurality of elongate load distributing and wall stiffening elements extends in divergent manner from the mounting at spaced positions around the site for location of the operating component. This structure can result in a significantly reduced support wall thickness. It is preferable that each stiffening element tapers away from each mounting and is directed towards a location at which side walls of the support member merge into each other. At this location, reinforcing fillets extend between the side walls and the support wall. A device is also provided to flex the support wall to increase locking action between the housing members when these are assembled.

Abstract: An electronics enclosure is provided with passive thermal management for a high power electronic units, for example a power amplifier for wireless telecommunications, the enclosure being suitable for mast head mounted units, or remotely located units exposed to a wide range of weather conditions. The use of heat pipes in place of a conventional heat sink provides for natural convection cooling and eliminates the need for fans. Appropriate selection of materials, using copper and aluminum respectively, for the construction of heat pipe and cooling fin assemblies provides a significant reduction in weight and volume is achieved relative to know units having conventional heatsinks and forced air convection cooling. Since the heat pipe efficiency decreases at low temperature, the power amplifier self heats the unit in cold weather and eliminates the need for heaters. This further reduces the power consumption and the size of the unit.

Abstract: A ferroelectric dielectric for microwave applications is provided comprising a polycrystalline perovskite phase of lead zirconate titanate dielectric material. Small grain size material is provided by a low temperature process, by a rapid thermal annealing process. A layer of amorphous ferroelectric precursor material is deposited and annealed in an oxygen containing atmosphere in the presence of water vapour, preferably with the addition of a few percent of ozone, and at a temperature of less than 500.degree. C. Advantageously, the method provides for formation of a ferroelectric material comprising lead zirconate titanate with a grain size less than 20 nm, with low film stress, high dielectric constant and low leakage current, which has excellent ferroelectric characteristics up to 10 GHz. This material has applications for capacitors, as filters, decoupling, coupling, and bypass elements and also for high frequency surface acoustic wave devices.

Abstract: A method for and apparatus of testing a multi-port RAM (random access memory) detect single port faults and inter port shorts in multi-port random access memories. The algorithm performs a conventional single-port test such as MARCH or SMARCH on one port of the memory and performs an inter-port test on all other ports. The algorithm does not impose any extra test time and requires the addition of only a few gates to a conventional single-port BIST controller, independently of the size of the memory. An address to select ports of the multi-port RAM includes a row address signal of a plurality of bits. A specific bit of the row address signal is changed.

Abstract: A digital data driver includes a differential amplifier having transistors which operate as a push-pull amplifier in class C mode. The transistors are conductive or non-conductive and controlled in response to a differential data input signal. The driver provides current to a load resistor of an external equipment and the direction of the current flowing therein is reversed in response to the input data. The differential amplifier transistors are connected to other transistors which provide source impedance to the external equipment. The source impedance of the driver is a controllable characteristic impedance of e.g., 50 .OMEGA..

Abstract: A large-capacity CAM (content addressable memory) is disclosed. RAM core cells are used to store the CAM data. The comparison function is not performed in the core cells, but rather in comparators which are placed adjacent to a plurality of core cells, in such a way that the plurality of core cells shares access to a single comparator. Access to the comparator is shared by a time-division multiplexed means, requiring a plurality of serialized operations. These operations are self-timed and transparent to the user, because they occur in a single cycle of the externally-supplied clock.

Abstract: A low voltage silicon bipolar RF (radio frequency) receiver front end includes a low noise preamplifier and double-balanced mixer. The receiver incorporates monolithic microstrip transformers for significant improvements in performance compared with silicon broadband designs. Reactive feedback and coupling elements are used in place of resistors to lower the front end noise figure through the reduction of resistor thermal noise, and this also allows both circuits to operate at supply voltages below 2 volts. Circuits fabricated using 0.8 .mu.m Bipolar CMOS technology provide a peak npn transistor transit frequency f.sub.T of 11 GHz. At a supply voltage of 1.9 volts, the measured input third order intercept point is +2.3 dBm with a 10.9 dB single-sideband noise figure. Power dissipated is less than 5 mW. The low noise amplifier input intercept is -3 dBm with a 2.8 dB noise figure and 0.5 dB gain. Power dissipation of the preamplifier is less than 4 mW from a 1.9 V supply.

Abstract: The invention provides a complex coupled distributed feedback (DFB) semiconductor laser device with energy band gap modulation. The device comprises an active region formed on a substrate, and a barrier region adjacent the active region, the energy band gap of the barrier region modulated along a cavity length direction to form a complex coupled grating. The modal gain is higher in the barrier region areas, having narrower energy band gap, due to higher material gain and higher optical confinement factor in these areas. Periodic modulation of the energy band gap of the barrier region produces gain (or loss) modulation and index modulation in the material of the active region, thus, gain coupling and index coupling mechanisms being provided. Methods of producing gain modulation in the DFB laser, and fabrication thereof are also provided.

Abstract: A gyrator includes shunt or feedback nodal capacitors and shunt lossy inductors without shunt load resistors. The effective nodal capacitance is reduced by the introduction of the shunt lossy inductors. The inductors act to discriminate against injected power supply noise, resulting in improved oscillator phase noise. The inductors produces less drop dc voltage than the resistive load, so that larger linear oscillation is obtained with improved oscillator phase noise.

Abstract: The invention relates to a passive liquid immersion cooling apparatus for electronic systems operating in thermally uncontrolled environments. The apparatus comprises an external shell, defining a chamber with a plurality of heat dissipating components disposed within the chamber and surrounded by the shell. The components are immersed into a low boiling point dielectric liquid partially filling the chamber. The shell has two portions, an upper portion of the shell adjacent the area above the liquid level which forms a vapor space, and a lower portion of the shell adjacent the liquid. The shell has an external heat transfer structure providing more efficient heat transfer from the upper part of the shell, for example, in the form of external fins extending outward from the shell, and an internal heat transfer structure in the form of internal fins extending inward from the shell and into the chamber. Preferably, the external fins extend along the upper portion of the shell only.

Abstract: A system and method for management of an interface for communications systems and devices using a recognizer having a limited time duration recognition window, based on mapping available time to a spatial representation. The system has particular application to management of a speech interface for a speech recognizer with a limited time duration recognition window. When the speech recognizer is on and a recognition window is opened, a timing signal is sent to the device and processed to provide spatial representation of the time remaining, e.g. in the form of an animation on a graphical user interface, or a recognizable pattern of stimulation using a haptic interface. As the recognition window advances and closes, the animation or pattern also changes and closes, e.g. diminishes in size, to provide the user with spatial information indicative of the time left in the recognition window.

Abstract: Management of speech and audio prompts, and interface presence, in multimodal user interfaces is provided. A communications device having a multimodal user interface including a speech interface, and a non-speech interface, e.g. a graphical or tactile user interface, comprises means for dynamically switching between a background state of the speech interface and a foreground state of the speech interface in accordance with a users input modality choice. Preferably, in the foreground state speech prompts and speech based error recovery are fully implemented and in a background state speech prompts are replaced by earcons, and no speech based error recovery is implemented. Thus there is provided a device which automatically subdue the speech prompts when a user selects a non-speech input/output mechanism.

Abstract: An electronic circuit in which a heat pipe is mounted on a substrate for transporting heat from one region to another, the heat pipe also being secured to the substrate at a plurality of positions along the heat pipe for the purpose of increasing the stiffness of the substrate. The heat pipe may extend across a surface of the substrate or around an edge of the substrate. Heat conductive paths from the heat source may be provided by a ground plane within the substrate or a heat conductor may extend from the heat source to the heat pipe at a position spaced from the substrate.

Abstract: An monolithic integrated circuit comprising a transistor-inductor structure is provided having simultaneously noise matched and input impedance matched characteristics at a desired frequency. The transistor-inductor structure comprises a first transistor Q.sub.1 which may be a common emitter bipolar transistor or common source MOSFET transistor Q.sub.1, a second optional transistor Q.sub.2, a first inductor L.sub.E in the emitter (source) of Q.sub.1, and a second inductor L.sub.B in the base (gate) of Q1. The emitter length l.sub.E1, or correspondingly the gate width w.sub.g, of Q1 is designed such that the real part of its optimum noise impedance is equal to the characteristic impedance of the system, Z.sub.0, which is typically 50.OMEGA.. The first inductor L.sub.E, provides matching of the real part of the input impedance and the second inductor L.sub.B cancels out the noise reactance and input impedance reactance of the structure.