Abstract: A transition splitting apparatus and method reduce a maximum transition rate of a digital signal. The apparatus and method are particularly useful for digital signal processing in communications and for performing digital transition timing testing on a device under test. The apparatus and method split a digital signal into two or more signals, while preserving the relative timing of transitions in the digital signal. A high frequency signal is partitioned by the apparatus and method into a plurality of equivalent lower frequency signals without loss of transition timing information. The apparatus is implemented with readily available components. The maximum transition rate of a digital signal is reduced by a factor of two or more, and is proportional to the number of output signals. A plurality of the apparatuses may be cascaded together into a system to achieve even greater reductions in maximum transition rates.

Abstract: A miniaturized ion analysis system with a contactless conductivity detection means is described for use in liquid phase sample analysis and detection. The device is formed by microfabrication of microstructures in novel support substrates. The detection means can be fabricated directly in the support body at the point of detection or other locations on the device or, alternatively, may be formed as part of a modular structure that is insertable into the device at the point of detection. In addition, a method is provided for analyzing ionic species present in a sample using the miniaturized ion analysis device. The invention herein is used for the analysis of ionic solutes in the liquid phase.

Abstract: Receive band filtering between the last two stages of an N-stage power amplifier can reduce the Rx band noise. There are N−1 interstage matching networks interposing N stage amplifiers, where N≧2. The interstage matching networks and stage amplifiers are electrically connected in series. The N−1th interstage matching network includes a receive band reject filter positioned proximate to the output of the N−1th stage power amplifier.

Abstract: Insertion delay associated with receiving and distributing a clock within an IC is removed using a DLL. The structure of a differential receiver in the feedback circuit of the DLL is substantially matched to the structure of an input differential receiver which receives and inputs a differential input clock into the DLL. In this manner, the insertion delay associated with the input differential receiver is removed from a delay-corrected clock output from the DLL. By substantially matching one or more aspects of the feedback circuit to one or more aspects of a clock distribution circuit for distributing the delay-corrected clock, the insertion delay associated with the clock distribution circuit can also be removed from the delay-corrected clock.

Abstract: An improved circuit board inspection system incorporates self learning techniques for accurate determination of Z-axis elevations of electrical connections. A Delta Z, referenced to a laser range finder generated surface map of the circuit board, is automatically determined from a series of cross sectional images of the electrical connections for each electrical connection on the circuit board. The Delta Z values for each electrical connection are stored in a data base from which customized Delta Z values for specifically defined board views may be calculated.

Abstract: A comparative conductivity detection system includes a sample channel assembly and a reference channel assembly. The sample channel assembly includes a sample-fluid channel, a drive electrode, and a detection electrode. The reference channel assembly includes a reference fluid channel, a drive electrode, and a detection electrode. The channels are formed as trenches in a planar substrate. Each electrode is capacitively coupled to its respective channel through a planar cover over the substrate. The drive electrodes are driven anti-synchronously (180° out of phase), while the signals induced in the detection electrodes are summed. The summed detection signal indicates the comparative conductivity of the sample and reference fluids. The reference fluid can, for example, include non-sample components of the sample fluid so that artifacts due to the non-sample components are cancelled in the comparative conductivity detector output.

Abstract: In known control loops to control a bias current of a laser device, the presence of a parasitic current drawn by an operational amplifier (114) of a monitoring circuit (100) introduces inaccuracies into measurements of mean power output of the laser device. The present invention provides the operational amplifier with an input stage (200) comprising MOSFETs (208, 210), thereby obviating the parasitic current.

Abstract: An optical measuring unit (20, 30) for measuring an optical property of an incoming optical beam (10) comprises a polarization converter (20) receiving the incoming optical beam (10) and providing a first output beam (50) and a second output beam (90) thereof, which are spatially separated and with substantially matching states of polarization. A polarization dependent analysis unit (30) receives the first (50) and the second (90) output beams from the polarization converter (20), and measures the optical property of both the first (50) and the second (90) output beams. The polarization converter (20) comprises a polarization dependent beam splitter (40) splitting up an incoming optical beam (10) into a first output beam (50) of the polarization converter (20) and into a second beam (60), each with a defined state of polarization but different from each other.

Abstract: In order to drive a single-mode laser device (126) using a differential-pair output stage (100) it is necessary to maintain collector terminals of transistors forming the differential-pair at a predetermined potential. Since the potential dropped across the laser device (126) is only about 1V, a Schottky diode (124) is provided between a cathode of the laser device (126) and a second supply rail (114) to raise the cathode by about 0.5V above the voltage of the second supply rail (114).

Abstract: A method of determining the ratio of the amplification factor before and after changing the amplification factor of a signal normalizer that amplifies the voltage amplitude of signals that are input from a signal generation means so that it stays within a predetermined range and outputs that voltage amplitude by using a signal generation means, which adds two sine-wave signals of the same frequency and voltage amplitude to form the output and controls the output voltage amplitude at any phase relationship between said two sine-wave signals by a phase control means, and an alternating-current voltage determination means, includes:

Abstract: Known differential pair amplifier circuits can suffer from transistor saturation resulting in a reduction in switching speed. An alternative to the differential pair amplifier circuit is a common-emitter configuration, but the common-emitter configuration lacks differential operability and results in ground bounce. The present invention therefore provides an amplifier circuit for an output stage 100 of a driver circuit comprising a pair of common emitter circuits (106, 114, 112, 122) cross-coupled by a pair of transistors (108, 110). Slow operation is therefore overcome whilst providing a differential output signal in response to a differential input signal.

Abstract: Heterodyne-based optical spectrum analysis involves filtering a heterodyne beat signal with at least one matched filter in order to improve the signal-to-noise ratio and the spectral resolution of the heterodyne-based optical spectrum analysis. In an embodiment, an input signal is combined with a swept local oscillator signal in an optical coupler. The combined optical signal is output to a receiver and a heterodyne beat signal is detected. The heterodyne beat signal is filtered by a matched filter unit and the filtered heterodyne beat signal is utilized to generate an output signal that is indicative of an optical parameter of the input signal. By utilizing the quadratic phase behavior of the heterodyne beat signal in signal processing, the resolution of a heterodyne-based OSA can be substantially improved over known heterodyne-based OSAs.

Abstract: An apparatus and method for selectively concentrating an analyte on an apparatus by evaporating solvent from the analyte. Concentration is performed by heating or by flowing a gas stream over the analyte to evaporate solvent from the analyte. The invention also provides a method to be used in conjunction with the apparatus.

Abstract: A system and method for measuring the group delay of an optical device under test (DUT) utilizes an optical frequency counter in conjunction with a test interferometer to compensate for the non-uniform frequency changes of an input optical signal used by the test interferometer to measure the group delay. The group delay of the optical DUT is measured using the zero-crossings of an AC coupled heterodyne beat signal produced by the test interferometer from the input optical signal. In the measurement of the group delay, phase changes in the heterodyne beat signal caused by the non-uniform frequency changes of the input optical signal are compensated by using the measured optical frequency of the input optical signal. The optical frequency is detected by the optical frequency counter. The detected optical frequency is indicative of the non-uniform frequency changes of the input optical signal.

Abstract: The present invention reduces multimoding of light generated by lasers. An asymmetric dispersion enhancer is included in a laser cavity to increase the asymmetric dispersion of the light amplified in the cavity. As a result, the side modes of the light passing through the cavity are asymmetrically disposed about the fundamental mode and, therefore, are amplified less in the cavity. Consequently, multimoding of the light is better suppressed.

Abstract: A reflection measurement method and apparatus measures reflection characteristics of a device under test (DUT) when access to the DUT is through a dispersive element. The method and apparatus measure a composite reflection response of a network that includes the DUT and the dispersive element coupled to the DUT via a transmission line. A reflection response of the dispersive element is isolated from a remainder of the composite reflection response of the network. A set of transmission parameters for the dispersive element is generated from the isolated reflection response of the dispersive element and is then applied to the remainder of the composite reflection response of the network to extract the reflection characteristic of the DUT.

Abstract: A method and a system to synchronize a time of day clock of a clock system. The method and system include a portable satellite timing system at a first location receiving a satellite signal comprising a first time of day signal. An internal clock of the portable satellite timing system is calibrated based on the first time of day signal to generate a second time of day signal. The portable satellite timing system is transported to a second location and coupled to the clock system. The second time of day signal is transferred from the portable satellite timing system to the clock system and the time of day clock is synchronized based on the second time of day signal. After a time period, the portable satellite timing system is transported to the first location.

Abstract: A laser generates a collimated laser beam which passes through a lens off-axis. The beam is focused at a focal plane on a substrate surface. A first position sensitive detector receives the laser beam reflected from the substrate surface through the lens to generate a first signal proportional to lateral beam offset. A beam splitter may be provided to direct a portion of the laser beam before passing through the lens toward a second position sensitive detector to generate a second signal proportional to laser beam pointing instability. Apparatus computes the difference between the first and second signals, the difference being a defocused error signal. It is preferred that the first position sensitive detector be located at a distance from the lens that is at least twice the lens focal length.

Abstract: A method of electrically connecting an electronic component to the flexible printed wiring board may comprise the steps of: Providing an air permeable platen having a substantially flat front surface and a back surface; placing the flexible printed wiring board on the front surface of the platen; lowering the pressure at the back surface of the platen; and electrically connecting the electronic component to the flexible printed wiring board.

Abstract: For delivery of ions from a higher pressure ion source to a mass analyzer operating at high vacuum, high pass ion filtration is effected within a dielectric capillary interface between the higher pressure ionization chamber and the lower pressure environment of a mass analyzer, by application of electrical potentials to end electrodes and to at least one electrode associated with the dielectric capillary between the ends, to create an end-to-end electric field generally opposing gas flow-assisted movement of ions from the upstream end to the downstream end, and to create a steeper voltage gradient along an upstream portion than along a downstream portion of the capillary. The voltage gradient along the steeper upstream portion of the capillary is sufficiently steep to cause ions having drift velocities below a lower limit to stall within the capillary. The respective potentials may be adjusted to increase the steepness of the upstream voltage gradient to increase the drift velocity lower limit.