Abstract: The present invention discloses a method of controlling transmitting frequencies of microwave source, which includes the following steps of: a) collecting reflection frequencies of a load according to a pre-set sampling rate; b) calculating a change rate of the reflection frequencies collected in the step a; c) setting a reflection frequency threshold and a change rate threshold; d) comparing the reflection frequencies and the change rate with the reflection frequency threshold and the change rate threshold respectively; wherein if the reflection frequencies or the change rate is less than the threshold goes to step e or returns to the step a; e) sending control signals to the microwave source and tuning the transmitting frequencies; and f) returning to step a. The present invention also discloses a microwave transmission system thereof. The present invention can be applied in controlling microwave source consists of single magnetron tube or multiple magnetron tubes.

Abstract: A power supply in a test and measurement device includes a stimulus having an output coupled to an amplifier in which an output signal from the stimulus controls an output level of the amplifier. The stimulus may include a Digital to Analog Converter. A measurement circuit detects the output level of the amplifier. The power supply includes an overpulse generator that can be structured to accept a desired amplifier output level, overdrive the stimulus at a first level for a first time period, and drive the stimulus at a second level for a second time period. The measurement circuit determines when the overpulse generator switches from driving the stimulus at the first level to driving the stimulus at the second level. The time period for driving the stimulus at the second level starts as the actual amplifier output level approaches the desired amplifier output level.

Abstract: The present disclosure relates to a magnetic angle sensor arrangement. The magnetic angle sensor arrangement comprises a multipole magnet rotatable around a rotation axis. A geometric arrangement of the multipole magnet is rotationally asymmetric with respect to the rotation axis. A plurality of magnetic field sensor circuits are placed around the rotation axis at predefined equidistant angular positions in a predefined axial distance from the multipole magnet, wherein each magnetic field sensor circuit comprises a first magnetic field sensor element sensitive to first magnetic field component and a second magnetic field sensor element sensitive to a second magnetic field component perpendicular to the first magnetic field component.

Abstract: A method includes obtaining a voltage phasor, a current phasor and a mechanical rotor angle of a source end generator. A receiving end generator impedance and a line impedance between the source end generator and a receiving end generator is also estimated. Furthermore, a swing angle between an internal voltage of the source end generator and an internal voltage of the receiving end generator as a function of obtained voltage phasor, current phasor, mechanical rotor angle and the impedances is estimated. A power swing condition is then determined based on the estimated swing angle.

Abstract: An apparatus for ascertaining and monitoring fill level of a medium in a container by means of a travel-time measuring method utilizing high-frequency measuring signals. An antenna having an antenna coupling region and an antenna region, or a waveguide having a probe coupling region and a probe measuring region extending into the container is included. Hollow spaces present in the antenna coupling region, in the antenna region, in the probe coupling region and/or in the probe measuring region are filled at least partially with a dielectric filling body. The dielectric filling body has internally at least one, hermetically sealed, reserved volume and the hermetically sealed, reserved volume is so embodied, that the dielectric filling body has a predetermined wave resistance and/or the high-frequency measuring signals have a predetermined propagation characteristic.

Abstract: A method and apparatus for measuring current includes sensing a first voltage at the output of an amplifier and computing a current based on the first voltage and the resistance of a first resistive element, which is electrically coupled between an inverting input of the amplifier and the output of the amplifier, if the first voltage is below a predetermined level. The method also includes sensing a second voltage at the output of a buffer and computing a current based on the first and second voltages and the resistances of the first resistive element and a second resistive element, which is electrically coupled between the inverting input of the amplifier and an input of the buffer and is also electrically coupled to the output of the amplifier through a at least one diode, if the voltage output from the amplifier is above the predetermined level.

Abstract: An immersion nozzle used for measuring a level of molten metal, wherein a first conductive portion and a second conductive portion which are made of carbon are imbedded in a pair of slots which are provided on the surface of the immersion nozzle separately from each other and along the longitudinal direction in such a way that the first and second conductive portions form integral parts of the surface of the immersion nozzle.

Abstract: A method and apparatus for measuring current includes sensing a first voltage at the output of an amplifier and computing a current based on the first voltage and the resistance of a first resistive element, which is electrically coupled between an inverting input of the amplifier and the output of the amplifier, if the first voltage is below a predetermined level. The method also includes sensing a second voltage at the output of a buffer and computing a current based on the first and second voltages and the resistances of the first resistive element and a second resistive element, which is electrically coupled between the inverting input of the amplifier and an input of the buffer and is also electrically coupled to the output of the amplifier through a at least one diode, if the voltage output from the amplifier is above the predetermined level.

Abstract: An amplifier circuit is used in a multimeter to amplify signals applied between a pair of test terminals. A voltage applied to one of the test terminals is amplified by a first operational amplifier configured as a voltage follower. An output of the first operational amplifier is applied to an inverting input of a second operational amplifier configured as an integrator. An output of the second operational amplifier is connected to the other of the test terminals. A voltage generated at the output of the second operational amplifier provides an indication of the magnitude and polarity of the voltage applied to the first and second test terminals.

Abstract: A circuit for measuring current drawn by a self-powered electronic protection device. The circuit monitors current in a polyphase alternating current (AC) power source by measuring current in a rectified secondary winding of a current transformer coupled to a phase current of the power source. The measurement circuit includes a measurement burden connected between the cathode of the current transformer rectifier and a switch. Closing the switch references the voltage drop across the measurement burden to a reference potential. A controller closes the switch while receiving measurements of the voltage drop. Because the voltage drop is referenced to a reference potential, it can be analyzed in a controller to detect a fault condition without being conditioned with an inverting amplifier or a difference amplifier.

Abstract: An amplifier circuit is used in a multimeter to amplify signals applied between a pair of test terminals. A voltage applied to one of the test terminals is amplified by a first operational amplifier configured as a voltage follower. An output of the first operational amplifier is applied to an inverting input of a second operational amplifier configured as an integrator. An output of the second operational amplifier is connected to the other of the test terminals. A voltage generated at the output of the second operational amplifier provides an indication of the magnitude and polarity of the voltage applied to the first and second test terminals.

Abstract: A voltage isolation circuit. The input voltage Vin is connected to a primary winding of a transformer T1 through a current limiting resistor R1. R1 is preferably sized such that the current flow in the primary at nominal input voltage is approximately 1 milliamp. Transformer T1 is wound as a current transformer with a fixed ratio between the primary and secondary windings. Thus, when 1 mA flows in the primary winding, 1 mA will also flow in the secondary winding. An inverting operational amplifier will continuously attempt to drive its inverting input to a zero potential through resistor R2. The voltage at Vout produced by the op-amp is a faithful replica of the voltage at Vin, but scaled according to the values selected for R1 and R2.

Abstract: An amplifier circuit is used in a multimeter to amplify signals applied between a pair of test terminals. A voltage applied to one of the test terminals is amplified by a first operational amplifier configured as a voltage follower. An output of the first operational amplifier is applied to an inverting input of a second operational amplifier configured as an integrator. An output of the second operational amplifier is connected to the other of the test terminals. A voltage generated at the output of the second operational amplifier provides an indication of the magnitude and polarity of the voltage applied to the first and second test terminals.

Abstract: A voltage isolation circuit. The input voltage Vin is connected to a primary winding of a transformer T1 through a current limiting resistor R1. R1 is preferably sized such that the current flow in the primary at nominal input voltage is approximately 1 milliamp. Transformer T1 is wound as a current transformer with a fixed ratio between the primary and secondary windings. Thus, when 1 mA flows in the primary winding, 1 mA will also flow in the secondary winding. An inverting operational amplifier will continuously attempt to drive its inverting input to a zero potential through resistor R2. The voltage at Vout produced by the op-amp is a faithful replica of the voltage at Vin, but scaled according to the values selected for R1 and R2.

Abstract: A physical quantity detector includes a pressure-responsive bridge circuit that outputs a detection voltage including a voltage component corresponding to atmospheric pressure and a voltage component corresponding to a change quantity from the atmospheric pressure, a filter that eliminates the voltage component corresponding to the change quantity from the atmospheric pressure, and a variable gain unit that amplifies a voltage difference between the detection voltage outputted from the bridge circuit and the filter output voltage that is free form the change quantity from the atmospheric pressure.

Abstract: The present invention is directed to a system and method for measuring a current in an integrated circuit comprising measuring a first output count from a first voltage controlled oscillator (VCO) using a first measurement voltage, simultaneously measuring a second output count from a second VCO using a second measurement voltage, and calculating the current in the integrated circuit using a voltage proportional to a difference between the first and second output counts.

Abstract: The invention concerns a device for measuring and/or monitoring a process parameter, with a sensor, an intermittently working measurement circuit, which has at least one energy storer unit, wherein the measurement circuit or individual components of the measurement circuit are activated for a predetermined time span, the so-called active phase, and with a control center, wherein the measurement circuit and the control center are connected with one another over a two-wire line and wherein a control-/evaluation-unit is provided, which activates the measurement circuit at the earliest, when the energy in the energy storer unit has reached a predetermined level.

Abstract: The invention relates to a method for producing at least one signal (oscillation signal), which indicates an oscillation in an electrical power supply system. In order to allow the oscillation behavior of an electrical power system to be detected safely and reliably at all times, an oscillation model is used which is formed from previous impedance values associated with the oscillation, or from variables dependent on these impedance values. A check is carried out to determine whether a further impedance value formed at that time or a variable which is dependent on this further impedance value differs from the oscillation model, and any occurrence of a further impedance value or of a variable dependent on this impedance value which differs from the oscillation model is assessed as the oscillation having stopped.

Abstract: A semiconductor device has a minute charge detecting circuit and a test circuit for suppressing harmful influence of stray capacitance and external noises during detection of a minute electric charge. The minute charge detecting circuit is constructed of a differential amplifier, a charge detecting capacitance and a charge-discharging switch. The test circuit is constructed of a charge transforming capacitance, a first switch and a second switch. A voltage variation of an input voltage signal for giving the minute electric charge is determined on the basis of a capacitance ratio of the charge transforming capacitance to the charge detecting capacitance. By making a capacitance value of the charge transforming capacitance smaller than that of the charge detecting capacitance, the voltage variation is increased so that the harmful influence of stray capacitance and external noises is reduced.

Abstract: A current sensing arrangement (10) includes a Hall effect sensor (16). A current-carrying line (14) of the arrangement (10) encircles the Hall effect sensor (16). A ferromagnetic sheet material (32) of the arrangement (10) covers a portion of the current-carrying line (14) and a portion of the Hall effect sensor (16).

Abstract: A current ratio device is used for forming a current transformer that can accurately scale down high currents to usable metering levels. The transformer has associated circuitry that renders it capable of functioning not only with ac and a mixture of ac and dc, but also when dc alone is present in the primary winding. The device employs a toroidal core and winding assembly that is cut along a plane containing the toroidal axis through a pair of diametrically opposite sections of the assembly that contain no windings, in order to separate the device into a pair of sub-assemblies that can be readily placed over a single turn primary, e.g. a busbar, without dismantling the same.

Abstract: Hydroxyaminomethylphosphonates of formula I ##STR1## where R.sub.1 to R.sub.5 are independently hydrogen, alkyl, cycloalkyl, aryl or phenylalkyl, R.sub.6 has the same meanings except for hydrogen, and R.sub.1 can also be trialkylsilyl, are useful stabilizers for organic materials subject to oxidative, thermal or actinic induced degradation.

Abstract: A portable temperature data recorder for temporarily storing plural sets of temperature data representative of temperatures at a single location or at different locations, and automatically transferring the stored temperature data to a data processing unit. The portable recorder has a connector for connection thereof to the data processing unit. The portable recorder may further have a connector for connection thereof to a stationary temperature detector or thermometer installed at each measurement location. Alternatively, the temperature recorder incorporate a temperature detector for measuring the temperatures at the measurement locations. A clock circuit may be provided in the portable recorder, so that the temperature data may be stored together with measurement time data. The temperature detector may be a radiation thermometer provided at the measurement location, or built in the portable recorder.