Disclosed is a high accurate measurement circuit, and the feature is using bias switching circuit for compensating front end offset, and the back end offset of amplifier is also cancelled. In the real measurement environment, offset exists in the amplifier of the measurement circuit has, and non-ideal effects also exist in the interface between measurement terminal and the measurement circuit, such as leakage current of chip package pins or mismatch of the circuit. The above non-ideal effects belong to front end offset and cannot be compensated by the prior arts. The disclosed structure uses the bias switch circuit and uses different switching method in the two measurement timings. By subtracting the measurement results for the two measurement timings, the front end offset is compensated, and the back end offset of the amplifier is also cancelled.

The present invention relates to a current sensor which measures alternating electromagnetic wave and a current breaker using the same, and the current sensor for alternating current is characterized in that it includes a sensor part arranged at a separation distance from the power wire through which alternating current is flowing; and a means of detecting alternating current by measuring the electromagnetic wave generated across the above sensor part by the electromotive force induced by the alternating current flowing through the above power wire, and in that the above means of detecting alternating current includes an amplifier.

A control device for an AC rotary machine includes an AC rotary machine having m sets of n-phase windings, a current detector, a power converter, and a control unit that calculates voltage commands on the basis of respective differences between a current command for the AC rotary machine and current detection values obtained by the current detector, and outputs ON/OFF signals to high potential side switching elements and low potential side switching elements of the power converter by comparing applied voltages calculated on the basis of the voltage commands with a carrier wave signal, wherein the current detector, when detecting currents flowing through the n-phase windings on the basis of currents flowing through current detection resistance elements that are inserted in series into the low potential side switching elements, obtains current detection values at two or more fixed timings over a single period of the carrier wave signal.

A sensing circuit includes a signal source circuit and a transient circuit. The signal source circuit provides a signal to the sensor via a conductor. When the sensor is exposed to a condition and is receiving the signal, an electrical characteristic of the sensor affects the signal, which is interpreted by the signal source circuit. When the sensing circuit is in a noisy environment, transient noise couples with the signal to produce a noisy signal. The transient circuit compares the noisy signal with a representation of the noisy signal. When the noisy signal compares unfavorably with the representation of the noisy signal, the transient circuit supplies a compensation signal to the conductor. The level of the compensation signal corresponds to a level at which the noisy signal compares unfavorably with the representation of the noisy signal.

An inspecting device of a display panel includes a contact including first probe pins that contact to data pads of a display panel and second probe pins that contact to common voltage pads of the display panel, a signal generator coupled to the first probe pins, the signal generator configured to generate a first data voltage corresponding to a first gray level and a second data voltage corresponding to a second gray level, a power generator coupled to the second probe pins, the power generator configured to generate a first common voltage and a second common voltage of which a voltage level is different from a voltage level of the second common voltage, and a defect detector configured to detect a defect of the display panel by removing a contact noise generated due to contact failure of the first probe pins and the second probe pins.

An apparatus is provided which substantially removes a perturbation signal from a pulse density modulated signal representing a combination of a signal to be measured and a perturbation applied to the signal to be measured. The removal of the perturbation is done by subtracting a correcting signal from the pulse density modulated signal. This approach introduces very little delay as it can be implemented by simple logic gates. It also provided enhanced immunity from the effects of bit errors.

A current detection circuit includes: a resistor in a current path; first and second signal transmission units that transmit signals of first and second terminal sides of the resistor; a first difference operation unit that executes a difference operation on the signals transmitted by the first and second signal transmission units; a noise-capturing transmission unit starting point; third and fourth signal transmission units connected with the noise-capturing transmission unit starting point; a second difference operation unit that executes a difference operation on the signals transmitted by the third and fourth signal transmission units; and a summing operation unit that executes a summing operation on the first and second difference signals, wherein the first signal transmission unit and the fourth signal transmission unit are disposed close to each other and the second signal transmission unit and the third signal transmission unit are disposed close to each other.

It is described an electronic device (1) for measuring an electric quantity, comprising: an analog-digital conversion module (2) configured to digitally convert time portions of an analog signal (S.sub.M(t)) to be measured alternated with time portions of a reference analog signal (S.sub.R(t)), for supplying respective first (D.sub.SM) and second pluralities (D.sub.SR) of digital values and a digital processing module (3) configured to: calculate a first mean amplitude (A1) of the first pluralities of digital values, and a second mean amplitude (A2) of the second pluralities of digital values; the first and second mean amplitudes being proportional to a mean gain value of the analog-digital conversion module (2); supply a ratio value (V.sub.RT) of the first mean amplitude to the second mean amplitude, representative of a measured amplitude of the analog signal (S.sub.M(t)) to be measured.

A method includes providing, by a signal source circuit of a sensing circuit, a signal to a sensor via a conductor. When the sensor is exposed to a condition and is receiving the signal, an electrical characteristic of the sensor affects the signal. The signal includes at least one of: a direct current (DC) component and an oscillating component. When the sensing circuit is in a noisy environment, transient noise couples with the signal to produce a noisy signal. The method further includes comparing, by a transient circuit of the sensing circuit, the noisy signal with a representation of the noisy signal. When the noisy signal compares unfavorably with the representation of the noisy signal, supplying, by the transient circuit, a compensation signal to the conductor. A level of the compensation signal corresponds to a level at which the noisy signal compares unfavorably with the representation of the noisy signal.

A method for detecting a transient of a voltage damper of an electric vehicle, wherein an electric vehicle is provided, having a voltage network and a voltage damper connected to the voltage network, and a measurement device connected to the voltage network detects a transient produced by the voltage damper as a result of a loading, a method for designing a voltage component of a voltage network of an electric vehicle, and a device for loading a voltage damper of an electric vehicle.