A system for electrical impedance tomography comprises: a plurality of electrodes; a plurality of impedance measurement units, each being associated with two or more electrodes, and wherein each impedance measurement unit comprises a current generator for generating a stimulation current between the electrodes and an amplifier for amplifying a measurement voltage between the electrodes; wherein the system is configured to perform a plurality of impedance measurements, wherein, for each impedance measurement, one impedance measurement unit is set in a stimulation mode for providing a stimulation current into the object, and wherein the impedance measurement unit being set in the stimulation mode is switched among the plurality of impedance measurement units, and wherein each impedance measurement unit is configured to be set in a calibration mode during at least one of the plurality of impedance measurements.

A system for electrical impedance tomography comprises: a plurality of electrodes; a plurality of impedance measurement units, each being associated with two or more electrodes, and wherein each impedance measurement unit comprises a current generator for generating a stimulation current between the electrodes and an amplifier for amplifying a measurement voltage between the electrodes; wherein the system is configured to perform a plurality of impedance measurements, wherein, for each impedance measurement, one impedance measurement unit is set in a stimulation mode for providing a stimulation current into the object, and wherein the impedance measurement unit being set in the stimulation mode is switched among the plurality of impedance measurement units, and wherein each impedance measurement unit is configured to be set in a calibration mode during at least one of the plurality of impedance measurements.

In one embodiment, a droop reference, comprising: a programmable low pass filter configured to filter a supply voltage; and a digital-to-analog converter configured to provide a scaled version of the filtered supply voltage.

Systems and methods for calibrating a conducted electrical weapon (“CEW”) to provide a predetermined amount of current for each pulse of the stimulus signal. Providing the predetermined amount of current, close thereto, increases the effectiveness of the stimulus signal in impeding locomotion of a human or animal target. The calibration process enables a CEW to calibrate the amount of charge in a pulse of the stimulus signal in the environmental conditions where the tester operates and also in the field where the environmental conditions may be different from the environmental conditions during calibration.

Systems and methods for calibrating a conducted electrical weapon (“CEW”) to provide a predetermined amount of current for each pulse of the stimulus signal. Providing the predetermined amount of current, close thereto, increases the effectiveness of the stimulus signal in impeding locomotion of a human or animal target. The calibration process enables a CEW to calibrate the amount of charge in a pulse of the stimulus signal in the environmental conditions where the tester operates and also in the field where the environmental conditions may be different from the environmental conditions during calibration.

Apparatus, systems, and methods for progressive corrosion detection are disclosed. An example apparatus includes a query generator to query a multiplexer channel to receive an output voltage, the multiplexer channel linked to a fin group of an electrode array, the fin group forming an open circuit in the absence of conductive crystal formation, a quantifier to determine, using a reference voltage, a difference between the reference voltage and the output voltage from the queried multiplexer channel, and a contamination level comparator to identify presence of conductive crystal formation based on the difference between the reference voltage and the output voltage.

Apparatus, systems, and methods for progressive corrosion detection are disclosed. An example apparatus includes a query generator to query a multiplexer channel to receive an output voltage, the multiplexer channel linked to a fin group of an electrode array, the fin group forming an open circuit in the absence of conductive crystal formation, a quantifier to determine, using a reference voltage, a difference between the reference voltage and the output voltage from the queried multiplexer channel, and a contamination level comparator to identify presence of conductive crystal formation based on the difference between the reference voltage and the output voltage.

Examples of operating an Intelligent Electronic Device (IED) during power swings, are described. In an example, voltage measurements for a phase is received and sampled. Root mean square (RMS) values of the voltage samples is calculated based on the voltage measurements. Delta quantities for each phase are calculated based on the RMS values. Each of the RMS values and delta quantities are associated with respective sampling instants. In response to a delta quantity being greater than a predefined threshold, a peak delta quantity is detected. A time interval between a sampling instant associated with the peak delta quantity and a sampling instant associated with a first delta quantity is determined. Based on a comparison of the time interval with a threshold time, a disturbance condition may be detected as a power swing and consequently, fault detection at the IED may be blocked.

Examples of operating an Intelligent Electronic Device (IED) during power swings, are described. In an example, voltage measurements for a phase is received and sampled. Root mean square (RMS) values of the voltage samples is calculated based on the voltage measurements. Delta quantities for each phase are calculated based on the RMS values. Each of the RMS values and delta quantities are associated with respective sampling instants. In response to a delta quantity being greater than a predefined threshold, a peak delta quantity is detected. A time interval between a sampling instant associated with the peak delta quantity and a sampling instant associated with a first delta quantity is determined. Based on a comparison of the time interval with a threshold time, a disturbance condition may be detected as a power swing and consequently, fault detection at the IED may be blocked.

During normal operation of a processor, voltage droop is likely to occur and there is, therefore, a need for techniques for rapidly and accurately detecting this droop so as to reduce the probability of circuit timing failures. The droop detector described herein uses a tap sampled delay line in which a clock signal is split along two separate paths. Each of the taps in the paths are separated by two inverter delays such that the set of samples produced represent sample values of the clock signal that are each separated by a single inverter delay without inversion of the first clock signal between the samples.