Abstract: A method of initiating and monitoring partial discharges in an insulating medium is disclosed. Apparatus for performing the method is also disclosed. A relatively low frequency time varying exciting waveform is applied to a sample of an insulating medium. A trigger pulse of short duration is superimposed on the exciting waveform to initiate partial discharge activity in the sample. The apparatus includes a trigger pulse generator with a synchronizing circuit which provides a pre trigger signal for an oscilloscope, allowing the resultant partial discharge activity to be monitored.

Abstract: An apparatus and method for the moisture content measurement of compressible materials using pressure to firmly hold surface probes against the material to be measured. The apparatus uses moisture measurement circuitry employed in frequency domain impedance or time domain reflectometry devices to obtain moisture content readings from materials. These moisture content readings are based on the apparent dielectric constant of the measured material. Subsurface air voids or gaps found in loose, layered materials undesirably influence moisture measurement readings by reducing the apparent dielectric constant of the measured material. Pressure is supplied through the apparatus to the material in the proximity of the surface probes, thereby reducing air voids to enhance measurement accuracy. The apparatus and method are especially useful for compressible organic materials such as forest duff, hay and soil.

Abstract: An apparatus and a method for detecting the presence and position of a wafer upon a semiconductor wafer support pedestal surface. Specifically, a wafer detector comprising a plurality of electrodes on a surface of the wafer support pedestal. The electrodes are coupled to a capacitance measurement circuit that measures the capacitance between the electrodes and generates a signal corresponding to a wafer's presence, location and chucking condition. The wafer's presence completes an electrical circuit between the electrodes, increasing the capacitance between the electrodes. As such, the presence of a wafer, the position of the wafer, and the condition of the wafer, i.e., wafer damage, can be detected upon a wafer support pedestal during wafer processing.

Abstract: Double-emitting and multiple-receiving capacitive measuring device: it comprises a scale equipped with an array of electrodes and a transducer, which moves parallel to and opposite the scale and is equipped with two emitting electrodes and an array of receiving electrodes distributed into N groups. The capacitive coupling between the different electrodes allows the position of the transducer to be determined. A generator emits two emission signals (E0, E1) in phase opposition on the two emitting electrodes of the transducer. The frequency of generated emission signals (E0, E1) depends upon the speed of displacement of the transducer. Processing means determine a dimension with the aid of N signals (R0, R7) received on the receiving electrodes. The more significant bits of the result are provided by a primary counting system using a first algorithm. The less significant bits are provided by a secondary precision system using a second algorithm.

Abstract: Pulse propagation analysis to ascertain whether and anomaly such as surface corrosion exists on a section of conductive member such as pipe. Anomalies such as surface corrosion result in localized velocity changes of pulses propagating along a conductive member. These localized velocity changes exhibit themselves in changes in waveform, rise and fall time, amplitude, and time delay of a pulse with respect to a fixed time reference. To allow such anomalies to be located, two pulses are generated such that they intersect at intersecting locations along the conductive member. The resulting modified pulses are analyzed for perturbations indicative of localized velocity changes.

Abstract: An orientation sensor especially suitable for use in an underground device is disclosed herein. This orientation sensor includes a sensor housing defining a closed internal chamber, an arrangement of electrically conductive members in a predetermined positional relationship to one another within in the chamber and a flowable material contained within the housing chamber and through which electrical connections between the electrically conductive members are made such that a comparison between an electrical property, specifically voltage, of a first combination of conductive members to the corresponding electrical property of a second combination of conductive members can be used to determine a particular orientation parameter, specifically pitch or roll of the sensor.

Abstract: The invention relates to a method for determining the transmission characteristics (H(jf)) of an electric line (2) in an ISDN system, in which a test signal (m(t)) is applied to the line (2) at one end, and at the other end of the line (2) the received signal (g(t)) produced owing to the test signal (m(t)) is evaluated.In order to be able to carry out such a method using a test signal having a crest factor of one with relatively little cost, use is made as test signal of a binary, bipolar random number sequence signal (m(t)) having the crest factor of one, and during a time interval corresponding to the period of the test signal (m(t)) the received signal (g(t)) is scanned and subjected to a Fourier transformation to obtain a spectral signal (G(jf)); the latter is complexly multiplied by a reference spectrum Mi(jf) to obtain an output signal (H(jf) which represents a measure of the transmission characteristics of the line (31).

Abstract: A spectrum analyzer measures a time difference between two or more signals with different carrier frequencies or a time delay between two or more signals with the same carrier frequency. The spectrum analyzer includes at least two measurement channels, each of the measurement channels has a frequency mixer, a local oscillator and an IF (intermediate frequency) filter for mixing an input signal to be measured with a local signal of the local oscillator to produce an IF signal which passes through the IF filter, and a demodulator provided in one of the measurement channels to demodulate the IF signal produced from the input signal to generate a trigger signal to start an operation of the other measurement channel.

Abstract: A positioner facilitates docking and undocking of an electronic test head with a device handler. The positioner provides for rotation of the test head about a first axis. The positioner includes a support structure for moving the test head along a second axis orthogonal to the first axis. The support structure accurately docks the electronic test head with the device handler.

Abstract: A delay element testing apparatus has a signal generator for generating a plurality of signals, at least one of which is variable in timing; a phase comparator for making a comparison of a relationship in terms of phasic anteriority and posteriority between the signal passing through a delay element under test and the timing-variable signal among the plurality of signals; and a test result output circuit, controlled by a control signal generated by the phase comparator, for outputting a signal indicating a quality of a delay characteristic of the delay element under test. Main parts of this testing apparatus can be provided on a substrate to realize an integrated having a function for testing delay elements included therein.

Abstract: A phase noise measurement system including a low noise programmable synthesizer and a receiver/down converter is provided. The low noise synthesizer provides L-Band Signals which can selectively exhibit low noise close-in or low noise far out. The receiver down converter provides for absolute, additive, and down converted/direct/multiple phase noise measurement.

Abstract: A safety compliance test instrument includes circuitry for performing insulation resistance and ground circuit tests such as a ground bond test, as well as high voltage AC and DC dielectric withstand or hipot tests. A micro-processor based controller provides control signals to a common power circuit, and accepts input of test parameters for all four tests through an integrated user interface including a keypad and menu display.

Abstract: A combustion state detecting apparatus for an internal combustion engine is capable of ensuring a satisfactory ion current detection sensitivity and reliability by preventing discharge of bias voltage to an ignition coil to thereby protect the bias voltage against lowering.

Abstract: A capacitor test apparatus for checking the capacitance of a capacitor without removing the capacitor from the circuit. Selection of the designated capacitance of the capacitor by means of a user-actuated selector switch automatically selects a test signal frequency such that the reactance of the capacitor matches a reference impedance. A indicator circuit compares the actual reactance with the reference impedance to indicate the deviation of the test capacitor from its designated capacitance. The test signal is a low level sine wave which does not exceed the conduction threshold of semiconductor junctions associated with the capacitor. A user-actuated switch is provided for discharging any charge present on the capacitor prior to testing.

Abstract: Method and apparatus for measuring distance includes a capacitance probe positioned adjacent a rotating member and within the housing of the rotating member such that the distance between the probe and rotating member can be measured. The rotating member and probe co-operate with each other so as to define a capacitor. An oscillator comprising a transmission line is electrically connected to the probe, the resonat frequency value of which is a function of the capacitance of the capacitor. The change in distance between the rotating member and the probe can therefore be measured.

Abstract: An electrical testing device for determining the continuity between ground terminals of an electrical power cord and determining the electrical grounding of an electrical power tool. The electrical testing device can also be configured to determine the proper polarity on each of the hot, negative, and ground cord wires of an electrical power extension cord. The electrical testing device includes a plastic case housing one or more batteries which supply power to a test button and the ground terminal of a female receptacle installed in the case. The top surface of the case includes a female receptacle, a test button, and a ground light. The top surface may also include a male plug and an additional female receptacle installed in the case. On the side of the case is an extending metal contact element. The test button is a single pole momentary contact test button.

Abstract: A test instrument for testing magnet wire which is provided which tests, collects and permits analyzing the effect of temperature, frequency, voltage and rise time associated with magnet wire use, and more particularly, the effects of those variables on the insulation of the wire, so as to evaluate the magnet wire performance and inverter controlled dynamoelectric machine applications.

Abstract: An SWR bridge with an accompanying set of connector saving adapters for connecting between the test port of the SWR bridge and a test device. The SWR bridge includes a branch opposite the test port which has an impedance set to substantially compensate for the impedance of the connector saving adapters. The connector saving adapters are configured to mate with connectors from two groups of test device connectors in both male and female versions, a first group including 3.5 mm, SMA and 2.92 mm connectors, and a second group including 2.5 mm and 1.85 mm connectors. To compensate for any capacitive mismatch between an adapter configured for a particular group of connectors and a given connector type, either a center conductor pin setback, an inductive counter bore in the outer conductor of the adapter, or a combination of the center pin setback and inductive counter bore may be utilized.

Abstract: A contact device having a plurality of nominally coplanar first contact elements makes electrical contact with corresponding nominally coplanar second contact elements of an electronic device when the contact device and the electronic device are positioned so that the plane of the first contact elements is substantially parallel to the plane of the second contact elements and relative displacement of the devices is effected in a direction substantially perpendicular to the plane of the first contact elements and the plane of the second contact elements. The contact device comprises a stiff substrate having a major portion with fingers projecting therefrom in cantilever fashion, each finger having a proximal end at which it is connected to the major portion of the substrate and an opposite distal end and there being one or two contact elements on the distal end of each finger.

Abstract: The phase response of a network is measured at uniform frequency intervals. A linear regression analysis is performed on samples of the phase response measured at frequencies within an aperture centered on a group delay frequency to obtain an estimate of the group delay of the network at that frequency. The process is repeated for a sequence of group delay frequencies to determine a trace of the group delay of the network across a range of frequencies.