Abstract: An embodiment provides a method for measuring a fluid parameter of fluid flowing in a channel, including: transmitting, using a transmitter of a device, directed energy carrying a signal toward a surface of a fluid in a fluid channel, so as to produce one or more reflections from the fluid surface; detecting, by at least one receiver of the device, one or more received signals associated with the one or more reflections so produced; and determining, based upon a measurement beam comprising characteristics of the transmitted and received signals, a fluid parameter to be measured using a processor of the device; wherein, a measurement beam characteristic is adjusted based on a distance from the device to the fluid surface. Other embodiments are described and claimed.

Abstract: An embodiment provides a method for measuring velocity of fluid flow in a channel, including: transmitting, using a transmitter, directed energy carrying a signal toward a surface of a fluid in a fluid channel so as to produce a plurality reflections from locations substantially spanning the entire width of the fluid channel; detecting, using a plurality of measurement beams, received signals from the plurality of reflections so produced; determining, based upon differences between transmitted and received signals, a plurality of localized velocities; and computing, from the plurality of localized velocities, a cross-sectional average velocity of fluid in the channel. Other embodiments are described and claimed.

Abstract: An embodiment provides a method for measuring a fluid parameter of fluid flowing in a channel, including: transmitting, using a transmitter of a device, directed energy carrying a signal toward a surface of a fluid in a fluid channel, so as to produce one or more reflections from the fluid surface; detecting, by at least one receiver of the device, one or more received signals associated with the one or more reflections so produced; and determining, based upon a measurement beam comprising characteristics of the transmitted and received signals, a fluid parameter to be measured using a processor of the device; wherein, a measurement beam characteristic is adjusted based on a distance from the device to the fluid surface. Other embodiments are described and claimed.

Abstract: An embodiment provides a method for measuring velocity of fluid flow in a channel, including: transmitting, using a transmitter, directed energy carrying a signal toward a surface of a fluid in a fluid channel so as to produce a plurality reflections from locations substantially spanning the entire width of the fluid channel; detecting, using a plurality of measurement beams, received signals from the plurality of reflections so produced; determining, based upon differences between transmitted and received signals, a plurality of localized velocities; and computing, from the plurality of localized velocities, a cross-sectional average velocity of fluid in the channel. Other embodiments are described and claimed.

Abstract: The present invention is directed to a method for an electrically conductive structure on a printed circuit board for connecting an element on the printed circuit board with other elements. The electrically conductive structure may include a contact pad on a first side of the printed circuit board and two or more connection pads on the first side of the printed circuit board. The two or more connection pads are in close physical proximity to the contact pad and electrically connected to the contact pad. The element on the printed circuit board is directly connected to one the two or more connection pads electrically. The structure permits various engineering changes to the electrical connections of elements on the printed circuit board by desoldering electrical connections to the two or more connection pad, by severing traces to the connection pads, or by severing the electrical connection between the connection pads and the contact pad.

Abstract: A novel thin wire connector cable and method for connecting an electrical test instrument to an electrical node of interest sealable within a vacuum chamber of an electrical testing device is presented. The thin wire connector cable includes a thin wire cable with a first end connectable to the test instrument and a second end comprising a connector electrically connectable to the electrical node of interest that lies within the vacuum-sealable chamber. The thin wire cable is routed from the vacuum-sealable chamber to the test instrument in between a flexible vacuum seal and an opening to the vacuum-sealable chamber such that when the vacuum is actuated, the thin wire cable is wedged between the seal and testing device. The thin wire cable is substantially thin enough so as to prevent more than a negligible amount of leakage between the thin wire cable and the flexible vacuum seal, which allows a vacuum to be generated and maintained.

Abstract: An electrically conductive structure and method for making circuit changes on a printed circuit board involves the use of electrically conductive tape to connect two previously unconnected points on the board. One or more sections of the tape may be used to form a low-profile contiguous path between two previously unconnected points on the board.

Abstract: The present invention is directed to a method and apparatus for an electrically conductive structure on a printed circuit board for connecting an element on the printed circuit board with other elements. The electrically conductive structure may include a contact pad on a first side of the printed circuit board and two or more connection pads on the first side of the printed circuit board. The two or more connection pads are in close physical proximity to the contact pad and electrically connected to the contact pad. The element on the printed circuit board is directly connected to one the two or more connection pads electrically. The structure permits various engineering changes to the electrical connections of elements on the printed circuit board by desoldering electrical connections to the two or more connection pad, by severing traces to the connection pads, or by severing the electrical connection between the connection pads and the contact pad.

Abstract: A novel thin wire connector cable and method for connecting an electrical test instrument to an electrical node of interest sealable within a vacuum chamber of an electrical testing device is presented. The thin wire connector cable includes a thin wire cable with a first end connectable to the test instrument and a second end comprising a connector electrically connectable to the electrical node of interest that lies within the vacuum-sealable chamber. The thin wire cable is routed from the vacuum-sealable chamber to the test instrument in between a flexible vacuum seal and an opening to the vacuum-sealable chamber such that when the vacuum is actuated, the thin wire cable is wedged between the seal and testing device. The thin wire cable is substantially thin enough so as to prevent more than a negligible amount of leakage between the thin wire cable and the flexible vacuum seal, which allows a vacuum to be generated and maintained.

Abstract: An electrically conductive structure and method for making circuit changes on a printed circuit board involves the use of electrically conductive tape to connect two previously unconnected points on the board. One or more sections of the tape may be used to form a low-profile contiguous path between two previously unconnected points on the board.

Abstract: A technique for minimizing the area occupied by traces on wireless fixture printed circuit boards of a printed circuit board tester on a per trace basis which ensures meeting maximum trace resistance and/or proper current delivery requirements for tests to be performed using the traces is presented. A printed circuit board implemented in accordance with the invention includes a plurality of conductive pads and a plurality of traces, each of which conductively connects at least two of said conductive pads. At least two of the traces may have differing respective cross-sectional areas predetermined to allow sufficient current to flow therethrough to drive devices connectable to said conductive pads. The cross-sectional area of each trace is calculated based on the minimum sufficient amount of current required to be delivered across the trace, the maximum allowed resistance of the trace, the trace length, and the characteristic resistance of the trace material.

Abstract: The present disclosure relates to a method and apparatus for determining the electrical continuity of an element of an electrical component, for example, a pin of a printed circuit assembly. The method comprises the steps of supplying an electrical stimulus to the element of the electrical component, positioning a sensor adjacent the element of the electrical component, the sensor having multiple axes along which the sensor is responsive to magnetic fields, receiving magnetic field signals created by the element of the electrical component with the sensor, producing electrical signals indicative of the magnetic field strength sensed by the sensor in multiple directions that correspond to the multiple axes, and comparing the electrical signals with predetermined limits associated with the element being tested. In a preferred arrangement, the sensor is provided with three axes which are oriented in orthogonal directions such that the magnetic signals from the element can be detected in three dimensional space.

Abstract: A method of determining whether an electrolytic capacitor is properly connected or reversed in an electronic assembly. In a first embodiment, a non-contacting probe is placed near but not touching the body of the device under test (DUT). One terminal of the DUT is driven by a stimulus (voltage source or current source) while the other terminal is connected to a reference voltage. A voltage is measured at the probe relative to the reference voltage and the device is properly oriented if the measured voltage exceeds a predetermined threshold. In a second embodiment, current through the probe is measured instead of voltage at the probe. In a third embodiment, a non-contacting probe is placed near but not touching both leads of the DUT. Each DUT lead is alternately driven by a stimulus and alternately connected to a reference voltage. For each of the two lead test configurations, a voltage at each DUT lead is measured and current through the non-contacting probe is measured.

Abstract: An algorithm selects probe locations for both test signal probes and ground probes in a short-wire board test fixture. The board test fixture connects a test system to a circuit board under test. The algorithm minimizes ground bounce. The algorithm envisions first superimposing an imaginary grid of squares over the circuit board. Then, ground probe locations are derived so that no more than five test signal probes for each ground probe reside within each of the imaginary squares and so that each critical test signal probe is associated within a preselected distance of a ground probe. In the preferred embodiment, the imaginary square measure 1.4 inches on a side, and the preselected distance is approximately one inch.

Abstract: Algorithms are set forth for positioning critical test signal pins in a short-wire board test fixture so as to efficiently minimize ground bounce. The board test fixture interfaces a test system to a circuit board under test. Critical signals are those signals susceptible to ground bounce. The test signal pins connect a ground plane in the board test fixture to pin cards interfaced to the board test system. Each pin card has a first column of test signal pins and a set of first ground pins. Moreover, each pin card has a second column comprising a set of second ground pins. In order to minimize ground bounce, no more than fifteen second ground pins per pin card are inactive. No more than two consecutive second ground pins per pin card are inactive. Any critical test signals are assigned within three pins of an exclusive first ground pin. Finally, any ordinary test signals are assigned more than four pins from any critical test signals.

Abstract: A driver circuit for use in a circuit board tester performs both functional and in-circuit tests on a given device under test (DUT). The tester provides a control signal representative of a command for the driver circuit to provide test signals to the DUT. The driver circuit incorporates two stages: a pre-driver stage and a driver stage. The pre-driver stage consists of an amplifier connected to fast switching transistors with the ability to move in and out of saturation rapidly. The amplifier receives control signals and the switching transistors provide actuation signals to the driver stage. The driver stage comprises two emitter follower transistors that operate exclusively in an unsaturated state. The driver stage provides test signals to the DUT in response to the actuation signals from the two switching transistors of the pre-driver stage. Additionally, the driver circuit may be programmed to change the output voltage amplitudes of the test signals.

Abstract: A driver circuit (10) for selecting particular values of backmatch impedance (Z) for a functional or in-circuit test system. The test system (100) generates the backmatch impedance select signals (32A), the control signals (32B), and the drive data (32C). A decode circuit (200) receives the backmatch impedance select signal and the control signals from the test system for activating one or more of a plurality of individual drivers. Each of the plurality of drivers has a three state control input (202A), a data input (212), and an output (214). Each output of the drivers is connected to an impedance (Z). Hence, a plurality of impedances are provided which are commonly tied together and connected to the transmission line (70). The test system connects one or more of the drivers together. When one driver is selected, that particular value of backmatch impedance is connected to the transmission line.

Abstract: An apparatus for preventing damage to the output stage of a driver circuit for use in an overdrive/functional tester, while the output stage is providing logic high or logic low signals, is shown to include a first sensor for sensing the current in the output stage, a second sensor for sensing the voltage in the output stage, a multiplier for multiplying the sensed current with the sensed voltage to determine the power dissipated in the output stage, a filter to account for thermal/time characteristics in the determined power dissipated and a comparator for comparing the filtered power with a power reference value and for generating an indication signal reflective of such comparison.

Abstract: A driver circuit for use in a circuit board tester which tester can perform both functional and in-circuit tests on a given device under test (DUT). The tester provides a test signal representative of a command for the driver circuit to provide logic high or logic low signals to a given device under test (DUT). The driver includes an output stage for providing desired logic high and logic low signals in response to the test signal; and switch circuitry, connected between the tester and the output stage, for preventing the test signal from reaching the output stage in response to a second control signal. The driver circuit is also shown to include an amplifier which, during operation of the driver circuit, receives feedback from the output stage. In addition, the driver circuit includes another output stage which provides a feedback signal when the driver circuit is in tri-state (deactivated).

Abstract: A method and apparatus for providing pulse signals from a driver circuit in an in-circuit overdrive/functional tester to a probe, which tester provides a control signal representative of a command for the driver circuit to provide logic signals, includes adjusting the transition time of the logic signals so that the transition time is equal to twice the time it takes the pulse signal to travel from the driver circuit to the end of the probe and back. The method or apparatus for adjusting the rise time of the control signal can include adjusting the slew rate of the control signal. Pulse signals produced by such a method or apparatus have clean edges, have slew rates which are twice as fast as the slew rates of the driver signals and have zero propagation delay when measured at the fifty percent point.