Abstract: An apparatus for analyzing the dielectric properties of a sample. A thin planar sample having a hole therein is positioned over two bottom electrodes having the hole over one of the bottom electrodes. An oscillator provides a first signal to one of the bottom electrodes and a second signal 180.degree. out of phase with the first signal to the second bottom electrode. A differential signal is obtained on the top electrode representative of the dielectric properties of the sample with the elimination of edge effects. A phase sensitive demodulator synchronized with the oscillator extracts the two components of the conductance and susceptance of the sample. A position sensor measures the thickness of the sample and is used to calculate the dielectric constant of the sample. Thereby, an accurate measurement of the dielectric properties of the sample is obtained without a complicated structure in order to eliminate edge effects.

Abstract: In an electrical supply network containing a generator, critical fluctuations in real power can occur. The load angle of the generator is representative of these fluctuations. The present invention provides a method which measures the real and reactive power flow, the current and the voltage on a line to the generator and feeds these measured values along with reactance values Y.sub.L and Y.sub.Q of the generator and line to a computing device. The computing device determines an output signal .delta. which represents the load angle of the generator and fluctuations in real power. The output signal .delta. is provided to an indicating device and/or a reactive power compensator.

Abstract: Measurements of the permittivity of samples over a very wide frequency range and a wide temperature range have previously involved such problems as changing parts of the measuring equipment in different regions of the frequency range, substituting one of the components of a bridge used as part of the equipment to obtain bridge balance, and limited permittivity resolution. The present invention employs a capacitance bridge formed by a sample held between electrodes, a series capacitor and a detector comprising a high input impedance amplifier and correlators. The bridge is balanced by applying voltages of known relative amplitude and phase constructed from outputs having relative phases of 0.degree., 90.degree. and 180.degree. of two phase-locked oscillators. The voltages are constructed using phase shifters, attenuators and summer-driver circuits. At low frequencies the applied voltages are obtained from a waveform synthesizer.

Abstract: An R/Z converter for use with a conventional digital multimeter (DMM) provides enhanced capabilities of the DMM in measuring impedance and other functions where DC measurements are undesirable. The R/Z converter converts the test voltage of a conventional DMM into a square wave that is applied to the device being tested. The voltage from the tested device is seen by the DMM as an average DC value that is proportional to the impedance of the device.

Abstract: A system and method for determining the complex impedance of a load, such as an antenna in an RF transmission system. The system samples both the voltage and current of the signal passing through a transmission line and directly derives digitally the impedance parameters independently of the amplitude or phase of the signal.

Abstract: An arrangement for determining on approximation the equivalent circuit diagram of an electrical or electronic element at high frequencies includes a measuring apparatus (4), to which the element to be represented as a two-port element (59) or a one-port element (1) is connected through connection members (2; 57, 58, 60) and which measures over a preselected frequency range the parameters of the stray matrix of the two-port element of the impedance or the reflection factor of the one-port element with the connection members. To the measuring apparatus (4) is connected an evaluation circuit (7), which corrects the measurement result by inclusion of two-port parameters of the connection member(s) determined before the measurement and which calculates for a preselected equivalent circuit diagram of the element from the corrected measurement result values of the equivalent circuit diagram elements by means of an optimization strategy.

Abstract: The circuit element being measured is connected to a signal source, a volt meter, a zero detection amplifier and a voltage controlled current source for drawing an electric current through the device to be measured in accordance with the output of the zero detection amplifier. Means are provided for changing the operating point of the zero detection amplifier in response to a measuring condition of the apparatus.

Abstract: Display section displays, on a screen, a zone marker for indicating, on a wide-band spectrum display area, that part of a wide-band spectrum which corresponds to a selected narrow-band spectrum to be displayed, and the wide-band spectrum, as well as said narrow-band spectrum which has been enlarged. First setting section changes a center frequency or a band width of said displayed narrow-band spectrum, in accordance with the change of the position or width of the zone marker. Second setting section cooperating with the first setting section changes the position or width of the zone marker in accordance with the movement of the center frequency or band width of the displayed narrow-band spectrum. Control section for controlling a measurement resolution and a sweep time in accordance with the magnitude of the displayed spectrum, so as to satisfy the formula:sweep time.gtoreq.band width/(measurement resolution).sup.2 .multidot.Kwhere K=a constant.

Abstract: A vector network analyzer comprising a circuit for measuring the real and imaginary components of the central spectral line in an RF pulse from a device-under-test is provided. The circuit comprises a modulator in response to a profiling pulse for modulating the amplitude of the RF pulse, mixers for down-converting the frequency of the amplitude modulated RF pulse, a narrow band filter for filtering the RF pulse having a bandwidth of 500 Hz and a synchronous detector responsive to the output of the crystal filter for providing a pair of dc outputs, which correspond to the real and imaginary components of the output of the device under test as the profiling pulse is shifted in time relative to the RF pulse.

Abstract: Low pass equivalent processing is a method for use with a network analyzer, that gethers a sequence of NDATA samples, each sample including real and imaginary components of a signal, over a frequency range from F1 to f2 in frequency steps of (f2-f1)/(NDATA-1), where f1 is greater than zero. The sequence of samples is processed to estimate a characteristic of the signal with respect to a selected discontinuity in the signal. The sequence of samples is converted to time domain, to generate time domain data over a range from zero to t. The selected discontinuity is identified as lying within a range of t1 to t2. Next, the phase of the time domain data is unwound to correct a portion of the phase error resulting from the one sided spectrum that is not dependent on the distance to the discontinuity through the network. Next, the magnitude peak JMAX of the data samples between time range t1 to t2, is determined.

Abstract: A preferred embodiment of a self-balancing reflectometer is disclosed in conjunction with a system including an RF source, an RF load, and an RF transmission channel that carries RF signals transmitted by the source to the load. The self-balancing reflectometer includes a load current sampler that generates a first sample signal related to load current by a first fixed value of gain and a load voltage sampler that generates a second sample signal related to load voltage by a voltage-responsive second variable value of gain. The first sample signal is subtracted from the second sample signal and the resulting difference signal is applied to the RF port of a double balanced mixer. The RF voltage signal appearing at the load is applied to the LO port of the mixer, which generates an IF signal that varies with both rapid load impedance modulation corresponding to load data and long term basal variations in load impedance unrelated to load data.

Abstract: A digital sine-wave generator, which includes at least one sine waveform memory, is read out by the output of a phase accumulator to generate a first digital sine wave, a second digital sine wave and a digital cosine wave. The first digital sine wave is converted by a D-A converter into an analog signal and then supplied to a measuring object. The output of the measuring object and the second digital sine wave are multiplied in a first multiplying type D-A converter, and the output of the measuring object and the digital cosine wave are multiplied in a second multiplying type D-A converter. The outputs of the first and second multiplying type D-A converters are respectively integrated by first and second integrators for a period which is an integral multiple of the sine wave period.

Abstract: An arrangement for detecting metallic particles carried by a fluid includes a metallic probe member which surrounds an elongated passage through which the fluid flows and which is constituted by a split tube having two marginal portions delimiting a gap which extends along said passage and completely separates the marginal portions from one another. Capacitors are arranged at the gap and alternating electric current is caused to flow in the probe member around the passage so that the probe member and the capacitors form a tank circuit having resonance characteristics that are influenced by any inclusion then present in the passage in a manner dependent on the electromagnetic properties of the inclusion. The character of any metallic particle then present in the passage is determined from variations in the alternating electric current that reflect the influence of such metallic particle on the resonance characteristics.

Abstract: An acoustic detection method and apparatus includes a source of high voltage pulses to be applied to an underground cable suspected of having a ground fault. As the pulses encounter the fault, acoustic energy is generated which may be sensed by a pair of transducers located along the path of the cable. The transducers are connected to signal processing circuitry which provides a display signal indicating which of the two transducers lies closer to the fault. The transducers are moved along the path of the cable in the direction indicated and the test is repeated until the fault is indicated as lying in the opposite direction. Thereafter the transducer are moved in the opposite direction in a shorter increment. This procedure is repeated until the direction to the fault changes each time the transducers are moved. The fault then lies midway between the midpoints of each of the two final transducer positions.