Abstract: A circuit for generating a linear current proportional to the displacement of the movable member of a transducer receives an undetermined supply voltage from a monitoring circuit which has a relatively high internal resistance. The circuit is provided with two parallel current paths with one path including a resistive potentiometer strip and other path including a transistor and resistor connected in series. The movable member of the transducer has an electrical contact member attached thereto with the contact member having one end making contact with the resistive potentiometer strip and with the other end thereof making contact with a conductive strip which is connected to the gate of the transistor so that the current drawn by the circuit will be linearly related to the movement of the movable member.

Abstract: The value of an unknown voltage is measured by applying a time-varying current from a reference voltage source through a resistor to a capacitor thereby to increase the voltage across the capacitor as a function of time, measuring the time Tr required for the voltage across the capacitor to reach a selected reference voltage when current from the reference voltage source is applied to the capacitor, restoring the voltage across the capacitor to its initial state, applying a time varying current from an unknown voltage source through a resistor to the capacitor thereby to increase the voltage across the capacitor as a function of time, measuring the time Tb required for the voltage across the capacitor to reach a selected reference voltage when current from the unknown voltage source is applied to the capacitor and calculating the unknown voltage from the times Tr and Tb.

Abstract: A memory cell system with properties of asymmetrical operation such that the occurrence of memory error due to certain environmental disturbances is detectable. The asymmetry of operation can be adjusted to set the level at which the disturbance is detected. Detection of memory error in the system can be used to shut off access to an associated memory array in order to prevent error in the array.

Abstract: A device for sensing the occurrence of destructive events and events involving mechanical shock in a non-intrusive manner. A pair of electrodes is disposed in a parallel configuration on a backing strip of flexible film. Electrical circuitry is used to sense the time at which an event causes electrical continuity between the electrodes or, with a sensor configuration where the electrodes are shorted together, to sense the time at which electrical continuity is lost.

Abstract: A return loss meter (100) for base stations comprises a first transceiver (10) having a first transmitter (12), a first receiver (22 and 30), and a first antenna (20), a second transceiver (50) having a second transmitter (52), a second receiver (62 and 70), and a second antenna (60), wherein the first transceiver and the second transceiver are cross-coupled using at least one directional coupler (16) capable of being switched. The return loss meter includes a device for measuring reflected and transmitted power of the first antenna via a first directional coupler (16) capable of being switched and via a device (74) capable of measuring received signal strength at the second receiver and a device for measuring reflected and transmitted power of the second antenna via a second directional coupler (56) capable of being switched and via a device (34) capable of measuring received signal strength at the first receiver.

Abstract: In an electric apparatus such as an electric power cable system, a high frequency pulse is induced on a conductive member such as a metal sheath, where partial discharge occurs in an insulation. The high frequency pulse is detected by means of a bypass lead wire, a metal foil electrode, a detecting coil, and the like provided on the electric apparatus without interrupting a live operation of the electric apparatus.

Abstract: A test instrument for determining whether an apparatus has a high voltage on the chassis thereof includes a meter, a probe and a socket for receiving a plug from the device being tested. The device also has a plug for insertion into an AC outlet. The test device first tests to determine that the AC outlet into which it is plugged is properly configured, then tests for a voltage on the chassis of a tested apparatus. The test is undertaken by connecting both the high and low contacts of the plug from an apparatus to be tested to the high voltage side of an outlet and connecting the probe to the ground contact of an outlet. Thereafter, when the probe is touched to the chassis of the apparatus the meter will indicate whether a voltage is present on the chassis of the appliance.

Abstract: A memory cell system is disclosed with properties of asymmetrical operation such that the occurrence of memory error due to certain environmental disturbances is detectable. The asymmetry of operation can be adjusted to set the level at which the disturbance is detected. Detection of memory error in the system can be used to shut off access to an associated memory array in order to prevent error in the array.

Abstract: A method for measuring the current flowing through a cow is disclosed. The method uses a four-terminal resistor precision measurement technique to accurately measure the electric current flowing through a cow as a result of voltages found on dairy farms. The four-terminal resistor technique allows the present invention to measure the current without the need to account for unpredictable environmental conditions on the dairy farm that may effect electrical contact resistances. The present invention uses Ohm's Law to determine current by dividing the voltage drop across a conductive path in the cow by the resistance of the conductive path. The elements utilized do not restrict cow movements and allow the cow to move about freely so as to enable dairy farmers to monitor conveniently and continuously for electric currents resulting from stray voltages on the dairy farm without interfering with daily farm activity.

Abstract: A signal envelope measurement preprocessing circuit including: input signal adjuster for interdicting a DC component contained in a signal input for measurement of the degree of flatness of an envelope or for passing only frequencies above a predetermined frequency; first and second half-wave rectifiers for separating into upper and lower portions the envelope of a signal output from the input signal adjusting means to thereafter detect the same; first and second frequency converters for converting a high frequency signal respectively from the first and second half-wave rectifiers into a low frequency signal; an analog-to-digital converters for converting a signal selected from low frequency signals output from the first and second frequency converters to a digital signal; and a system controller for comparing a data output from the analog-to-digital converter with a data stored on an internal program to thereafter measure the degree of flatness of a signal envelope.

Abstract: A bridge-type capacitance transducer comprising four active components is disclosed. The symmetry of this transducer is maintained in the presence of capacitance change induced by motion. Consequently, there is greater immunity to extraneous stray capacitances, thus greater sensitivity and range of linearity. Sensitivity is further increased by means of synchronous detection at the output.

Abstract: A load short-circuit state detection circuit has a driver including X and Y terminals between which an inductive load is connected and receiving drive signals. The detection circuit further includes a first transistor whose base is connected to the X terminal and whose collector is supplied with a voltage, a second transistor whose base is connected to the Y terminal and whose collector is also supplied with a voltage, a first constant current circuit connected to an emitter of the first transistor through a first resistor and a second constant current circuit connected to an emitter of the second transistor through a second resistor. A comparator is provided for comparing a voltage of a node between the first resistor and the first constant current circuit with a voltage of a node between the second resistor and the second constant current circuit.

Abstract: A system and method for testing underground electric cables, while in service, for active corrosion and degree of neutral loss. The method is conducted by applying a non-harmonic selected frequency signal to the neutral(s) of the underground cable connecting a pair of structures, e.g., power transformers, from a variable frequency generator of the system. The test is conducted by a surveyor wearing foot electrodes which contact the earth as the surveyor walks along the earth over the cable in a close interval steps. At each step, direct current (DC) potentials are monitored by a voltmeter between a copper-copper sulfate electrode carried by the surveyor and brought into contact with the ground at each step and the transformer ground. The potential of the gradients between the foot electrodes at the selective frequency and at the native alternating current (AC) is also measured by the voltmeter. These measurements are recorded at a stationary location on a digital data logger and/or computer.

Abstract: An in-circuit test apparatus includes a constant voltage source that supplies constant voltages and a current amplification circuit that outputs a constant current based on the constant voltages. A switch transfers the constant current from the current amplification circuit to an inversion amplifier that inversion-amplifies the constant current transferred by the switch. Additionally, a relay circuit transfers the inversion-amplified signal to a test board having a capacitor inserted into the test board. The capacitor charges with the constant current transferred by the relay circuit for a predetermined time period. A voltage follower amplifies the charging voltages on the capacitor to prevent the charging voltage from being discharged due to an internal resistance of the capacitor. Further, a comparison circuit compares the charging voltage on the capacitor with a reference voltage to sense the capacitance of the capacitor and to sense reverse insertion of the capacitor.

Abstract: Test apparatus for a high voltage cable installation includes a high AC voltage source having the frequency range intended to be carried by the cable installation and a high DC voltage source. A switch alternately passes positive and negative polarities of the DC voltage, and the AC voltage source and the alternating polarity DC voltage output from the switch are coupled while isolating the voltage sources from each other. The resulting alternating polarity DC-biased AC voltage is injected into the cable installation to produce indications of incipient faults.

Abstract: Apparatus for displaying operating conditions of a device in which voltages that are produced when respective operating conditions exist are formed into a series of pulses with a bracket pulse on at least one end of the series and a display of indications of the presence of pulses at locations corresponding to their positions in the series.

Abstract: A transceiver (203) instructs a RF switch matrix (200) to direct its output to any one of M outputs and likewise sends information related to the power and frequency of the RF input signal and the switched output to an OMC (112). Each output of the matrix (200) is adjusted by an attenuator bank (218) and fed to a spectrum analyzer (233). OMC (112) relays the power, frequency and switched output information to a computer (239) which instructs the spectrum analyzer (233) to perform a power measurement at the frequency of the RF input signal. The computer (239) then determines which outputs of the matrix (200) were switched based on the power level of the RF input signal, the measured power level of the adjusted output signal and a relationship of the different predetermined levels within attenuator bank (218) and verifies by comparison to the switched output information.

Abstract: An apparatus for detecting frequency of an input signal by counting the pulses of a reference signal of a predetermined frequency within one cycle of the input signal is disclosed. The apparatus includes a first and a second latch for latching the number of pulses of the reference signal for two consecutive periods of the input signal. In response to the reference signal, a comparator is used to compare the output value of the first and the second latch. When they are different, a flip-flop generates an interrupt signal to a microprocessor. The microprocessor reads the updated number of pulses and generates an updated frequency value based on the updated number of pulses and the predetermined frequency of the reference signal.

Abstract: For calibrating a network analyzer which has two test ports adapted to be connected to an object under test by means of lines or through free-space, the transmission and reflection parameters are measured in a first calibrating measurement either on a line which is connected in reflection-free fashion between the two test ports or on the free-space connection. Subsequently two or three further calibrating measurements are performed with the same free-space connection or the same line, respectively, on calibration standards which are implemented by reflection-symmetrical and reciprocal interfering objects or discontinuities inserted at two or three different positions in the free-space connection or the line, respectively.

Abstract: A simultaneous signals frequency measurement receiver comprising a number n of delay line correlators, with a complete set of n, delays, a number 2n of digitizers, computational means to define an m.times.m matrix R, to calculate the mathematically defined eigenvectors of R, to calculate the simultaneously received signal frequencies. This receiver measures the frequencies of simultaneous signals based on a digitized sample of all the correlation outputs of a complete set of delay line correlators.