Abstract: A deadweight pressure standard provides improved measurement accuracy and repeatability. The standard includes a flow regulator having a first valve controlled by a first pair of non-hysteresis sylphons, and a supply regulator having a second valve controlled by a second pair of non-hysteresis sylphons. The first and second valves achieve an equilibrium state between the supply regulator and the flow regulator. The second valve regulates pressure generated by an applied pressure supply. A mass-to-pressure transducer transforms an applied gravitational force into a reference pressure regulated by the first valve. The center of pressure force on the first pair of non-hysteresis sylphons, and the center of pressure force on the first valve, are exerted along a first reference axis. The center of pressure force on the second pair of non-hysteresis sylphons, and the center of pressure force on the second valve, are exerted along a second reference axis.

Abstract: Systems and methods for efficiently conveying one or more broadband communication channels over a transmission medium. Communication is effected by transforming an incoming digital bit stream into a prime frequency information stream that includes a plurality of prime frequency components. This transformation can be accomplished through the use of a plurality of mathematical basis functions. The prime frequency information stream is then transmitted over the transmission medium. More particularly, digital bit streams carried on one or more incoming channels are in the form of binary “on” and “off” bits. These digital bits are converted into a plurality of prime frequency components which together comprise a prime frequency information stream. The conversion process maps each of respective incoming digital bits to a corresponding one of a group of orthogonal basis functions.

Abstract: Systems and methods for efficiently conveying one or more communication channels over a transmission medium. Communication is effected by transforming an incoming digital bit stream into a Hermite-Gaussian information stream that includes a plurality of Hermite-Gaussian packets. This transformation is accomplished through the use of a plurality of Hermite-Gaussian basis functions. The Hermite-Gaussian information stream is then transmitted over the transmission medium. More particularly, digital bit streams carried on one or more incoming channels may be in the form of binary “on” and “off” bits. These digital bits are converted into a plurality of Hermite-Gaussian waveform components which together comprise a Hermite-Gaussian packet. The conversion process maps each of respective incoming digital bits to a corresponding one of a group of Hermite-Gaussian functions.

Abstract: A mass transfer system offers the simultaneous transfer and time-saving efficiencies transfer techniques, while also offering the flexibility of prior-art free techniques. A mass transfer mechanism and an associated software control mechanism are equipped with the ability to retract a plurality of lifting arms (6), in a manner so select which of the processing stages (2) the lifting arms (6) will address for each transfer step, while omitting those steps for which transfer is not yet required.

Abstract: The deposition rate of MCVD processes is enhanced by applying at least a first and a second independently controlled heat source to a plurality of reactants which are used to form deposited particulate matter. The first heat source is adjusted so as to provide at least a specified rate of reaction for the reactants, and the second source is adjusted so as to provide at least a specified deposition rate for the particulate matter.

Abstract: Systems and methods for determining the spectral arrangement of a composite signal that includes a plurality of individual signals, so that one or more individual signals may be separated from the composite signal. According to one embodiment, a first set of samples are taken from the composite signal during a first time duration, and a second set of samples are taken from the composite signal during a second time duration. The first and second time durations are selected such that at least a portion of the second time duration does not temporally overlap the first time duration. A weighing function is applied to the first and second sets of samples to generate weighted sample sets. The autocorrelation between the first and second weighted sample sets is measured, thereby providing information about the bandwidth occupancies of each of a plurality of individual signals within the bandwidth of the composite signal.

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: In an RF filter having an input terminal, an output terminal, a plurality of resonator elements, and a plurality of coupling reactances for coupling one resonator element to another resonator element, for coupling the input terminal to a resonator element, and for coupling the output terminal to a resonator element, techniques are disclosed for providing an RF filter having an electronically tunable center frequency and an electronically tunable bandwidth. According to a specific embodiment disclosed herein, a first shunt reactance is provided from the input terminal to ground, and a second shunt reactance is provided from the output terminal to ground. The values of the coupling reactances remain constant, while the values of the resonator elements, the first shunt reactance, and the second shunt reactance are tuned to provide a specified filter bandwidth and/or a specified center frequency.

Abstract: Detection of the existence, magnitude, and frequency of occurrence of a plurality of ESD events is achieved by using an envelope detector to process signals generated by ESD events and received by an antenna. The ESD event detector includes an antenna for producing a signal waveform in response to electromagnetic fields incident thereupon, a demodulator coupled to the antenna for generating an envelope waveform that is related to the envelope of the signal waveform, a threshold window discriminator coupled to the demodulator for generating an indication signal if the envelope detected by the demodulator has a magnitude between a first and a second threshold, and a counter coupled to the threshold window discriminator for counting the number of indication signals received from the threshold window detector.

Abstract: Improved wireless telephone call admission methods for admitting new and/or handoff calls into a wireless telephone network having a plurality of communications channels. One such method, fractional guard channel call admission, effectively reserves a non-integral number of guard channels for handoff calls by rejecting new calls in accordance with a probability value that is dependent upon the current channel occupancy. Fractional guard channel call admission results in a significant reduction of new call blocking when a fixed constraint is placed on the handoff call blocking probability. Fractional guard channel call admission also provides improvements over the integral guard channel policy by minimizing the number of required channels when fixed constraints are placed on both the new call blocking probability and the handoff call blocking probability.

Abstract: Novel rate-based flow control methods operate in conjunction with a data communications network. Such networks include a plurality of interconnected nodes, wherein each node is adapted for connection to any of a plurality of sources. The sources send data to, and receive data from, the nodes. The path that data follows in traveling from a first source, through one or more nodes, to a second source, is referred to as a virtual circuit path. Each node includes a processor and an associated memory for storing a data queue of data received from sources. According to one embodiment, referred to as first-order rate-based flow control, a node allocates a data transfer rate to a source based upon the difference between the current queue length at that node and the queue threshold of that node multiplied by a gain.

Abstract: An improved control voltage generator for use with a voltage-controlled oscillator (VCO), so as to enable VCO operation at low supply voltages of less than three volts. The control voltage generator includes a phase comparator, a charge pump, a switched voltage multiplier, and a control voltage filter. The output voltage of the phase detector is coupled to a sampling terminal of the charge pump, a power supply terminal of the charge pump is coupled to an output terminal of the switched voltage multiplier, and a voltage input terminal of the switched voltage multiplier is coupled to a first, reference signal. The charge pump, powered from the power supply terminal, generates a waveform including a plurality of pulses. Each of the plurality of pulses has a time duration substantially proportional to the voltage present at the sampling terminal.

Abstract: Test points (20, 24) placed at selected nodes (16) within a circuit (10) based on a cost function that accounts for (a) the global improvement in testability and (b) the penalty in circuit performance associated with propagation delays attributable to such test points. By accounting for both the global impact on testability and circuit performance degradation, the cost function maximizes fault coverage while achieving nearly minimal impairment of circuit performance.

Abstract: Methods and systems for non-invasive RF circuit testing, and/or for RF signal redirection, are disclosed. These methods and systems are used in conjunction with an RF circuit having a first circuit element, a second circuit element, a microstrip line coupling the first circuit element to the second circuit element, such that RF power flows along the microstrip line from the first circuit element to the second circuit element, and an RF test port for testing the RF circuit. A first removable electrical impedance is placed in physical proximity to the microstrip line to produce a first impedance mismatch at the microstrip line, such that some RF power is reflected by the mismatch back to the first circuit element. A second removable electrical impedance is placed in physical proximity to the microstrip line, such that the microstrip line is coupled to the RF test port.

Abstract: Improved radio receiver designs are disclosed that can be used in the operational environment of wireless communications. The radio receiver includes a signal input terminal, a variable-current RF signal amplifier, a demodulator, and a controller. The variable-current RF signal amplifier has an input terminal for accepting RF input signals, an output terminal for generating an amplified version of the RF input signals, and a current control terminal for controlling the current consumption of the RF signal amplifier. The signal input terminal is coupled to the input terminal of the variable-current RF signal amplifier, the output terminal of the variable-current RF signal amplifier is coupled to the demodulator, and the current control terminal is coupled to the controller. The controller is also coupled to the demodulator. A received signal, including any noise and/or interference, is coupled to the signal input terminal.

Abstract: Pseudorandom Boundary-Scan testing of a interconnects within a system (10) is accomplished by first generating a pseudorandom pattern and then filtering the pattern before application to the system to modify values within each pattern that could cause a signal conflict. Each response generated by the system upon application to the system is also filtered to mask non-deterministic values with the response. The filtered response is compared to a set of signatures representing a fault-free condition to detect faults within the system.

Abstract: A method is provided of trimming the optical coupling ratio of an optical coupler to a prescribed value. The optical coupler is formed from a plurality of waveguides which each include a core and cladding. In accordance with the method, an irradiation energy is selected that is absorbed by portions of the waveguides located in a coupling region. A dosage of radiation is applied to the waveguide portions at least sufficient to adjust the optical coupling ratio to the prescribed value. The radiation, which may be absorbed by the cladding and/or the core of the waveguides, causes a change in the refractive index difference between the core and cladding of the waveguides. This change in the refractive index difference will result in a change in the optical coupling ratio of the device.

Abstract: A method and apparatus aligns device components based on an analysis of an image of features of the components to be aligned. The image is analyzed for deviation in component alignment, and a signal, based on the deviation, is sent to a positioning apparatus to adjust the position of the components relative to each other. The image of the components is advantageously a top view which permits measuring deviations in alignment of features on the top surfaces of components. The components are advantageously bonded together after alignment, and the alignment accuracy of the bonded components is checked.

Abstract: Systems and methods for providing secure smart card transactions are disclosed. Smart cards are arranged in a smart card hierarchy, the hierarchy including a first smart card at a first hierarchical level and a second smart card at a second hierarchical level higher than the first hierarchical level. A smart card reader is equipped to read smart cards and to accept personal identification (PIN) number inputs. According to one embodiment, a first PIN number is stored on the first smart card, the first PIN number corresponding to the first hierarchical level. A first security key is also stored on the first smart card. A second PIN number is stored on the second smart card, the second PIN number corresponding to the second hierarchical level. A second security key is stored on the second smart card. The PIN numbers and security keys are used to selectively lock and/or unlock a smart card.