Some embodiments include a method for monitoring usage of electrical power of a structure using an electrical power monitoring system. The structure can have one or more main electrical power lines that supply the electrical power to a first load in the structure. The method can include calibrating the electrical power monitoring system. A first raw current in the one or more main electrical power lines and first calibration data can be generated while calibrating the electrical power monitoring system. The method also can include storing the first calibration data and a measurement of the first raw current. The method additionally can include measuring a second raw current. The method further can include calculating a first measured current. The method additionally can include displaying the first measured current. Other embodiments of related systems and methods are disclosed.

Resistor voltage dividers are commonly used to create reference voltages, or to reduce the magnitude of a voltage so it can be measured. Many measurements in test and measurement or calibration applications regularly require accuracies within the sub-part per million (ppm) range, e.g. 0.1 ppm to 1.0 ppm. However, the continued drive for improved accuracy in calibration, standards, and measurements on circuits and components means many measurements and measurement systems are operating at 50 parts per billion (ppb) and below to approximately 10 ppb. At these levels even relatively simple passive elements such as voltage dividers cannot be used without calibration and that these calibrations may be required at frequencies substantially higher than the other elements within the test and measurement equipment. Accordingly, the inventors have established a self-contained voltage divider with internal calibration allowing the voltage divider to be calibrated for every measurement if necessary.

A magnetic field sensor comprises a first coil configured to generate a magnetic field having a first frequency and induce a reflected magnetic field from a target. A second coil configured to generate a diagnostic magnetic field having a second frequency is included. The diagnostic magnetic field is configured not to induce a reflected magnetic field from the target that is measurable by the magnetic field sensor. At least two magnetic field sensing elements detect the reflected magnetic field and the diagnostic magnetic field and generate a signal representing the reflected magnetic field and the diagnostic magnetic field. A processing circuit is coupled to the at least two magnetic field sensing elements and configured to receive the signal, extract a diagnostic magnetic field portion of the signal representing the diagnostic magnetic field, and generate an error signal if a fault is detected.

Disclosed is a calibration circuit and method. The circuit includes: a DAC that outputs an analog parameter and includes output parameter adjustment circuitry; a comparator that receives a reference parameter and the analog parameter; and a control circuit (with select logic) connected to the comparator and DAC in a feedback loop. During a calibration mode, the magnitude of the analog parameter is adjusted by DAC step in one direction and the feedback loop is used to perform a binary search calibration process. During an operation mode, the magnitude of the analog parameter is adjusted by DAC step in the opposite direction. The select logic selects the DAC step identified by the calibration process or the next higher DAC step as a final DAC step. The control circuit outputs a final DAC code corresponding to the final DAC step and the DAC generates a calibrated parameter based thereon.

A calibration device adapted to be used with a measurement instrument includes a controller, two or more ports, two or more power measurement circuits each connectable with one of the two or more ports, and a non-transitory computer readable storage medium accessible to the controller within which characterization data related to the two or more ports is storable. The calibration device is adapted to be connected with the measurement instrument via a data bus to transmit data and receive commands between the controller and the measurement instrument. The two or more ports are adapted to be interchangeably connectable with ports of the measurement instrument. When the ports of the measurement instrument are connected with the two or more ports of the calibration device and a signal is transmitted by the measurement instrument to the calibration device, a connection configuration between the measurement instrument and the calibration device can be determined based on a detection of power at the two or more power measurement circuits.

The present invention relates to resistance calibration and in particular to resistance calibration in the context of semiconductor integrated circuitry.

Resistor voltage dividers are commonly used to create reference voltages, or to reduce the magnitude of a voltage so it can be measured. Many measurements in test and measurement or calibration applications regularly require accuracies within the sub-part per million (ppm) range, e.g. 0.1 ppm to 1.0 ppm. However, the continued drive for improved accuracy in calibration, standards, and measurements on circuits and components means many measurements and measurement systems are operating at 50 parts per billion (ppb) and below to approximately 10 ppb. At these levels even relatively simple passive elements such as voltage dividers cannot be used without calibration and that these calibrations may be required at frequencies substantially higher than the other elements within the test and measurement equipment. Accordingly, the inventors have established a self-contained voltage divider with internal calibration allowing the voltage divider to be calibrated for every measurement if necessary.

A measurement accessory device connectable to a measurement apparatus or to a device under test wherein the measurement accessory device comprises means for providing characteristic data of said measurement accessory device in machine readable form used by said measurement apparatus during measurement of said device under test.

An apparatus to estimate parameters of a radio frequency (RF) signal may include a voltage sensor configured to provide an indication of a voltage of the RF signal as well as a current sensor configured to provide an indication of current conducted by the RF signal. The apparatus may additionally include an analog-to-digital converter coupled to an output port of the voltage sensor and the current sensor, wherein the analog-to-digital converter is configured to provide digital representations of an instantaneous voltage and an instantaneous current of the RF signal. The apparatus may additionally include one or more processors configured to transform the digital representations of the instantaneous voltage and current into frequency domain representations of a complex voltage and complex current.

A broad band coaxial load includes a conductive rod that is held coaxially within a coaxial support. The coaxial support includes a body containing a round hole with three axial sections (that include an exponential funnel), a plurality of radially oriented contact springs, and a cylindrical hole geometrically/dimensionally matching to the diameter of the conductive rod.