A method measures a characteristic of a SUT using a signal measurement device having multiple input channels. The method includes digitizing first and second copies of the SUT in first and second input channels to obtain first and second digitized waveforms; repeatedly determining measurement values of the SUT characteristic in the first and second digitized waveforms to obtain first and second measurement values, respectively, each second measurement value being paired with a first measurement value to obtain measurement value pairs; multiplying the first and second measurement values in each of the measurement value pairs to obtain measurement products; determining a mean-squared value (MSV) of the SUT characteristic measurement; and determining a square root of the MSV to obtain a root-mean-squared (RMS) value of the measured SUT characteristic, which substantially omits variations not in the SUT, which are introduced by only one of the first or second input channel.

An apparatus comprises a switch, a current monitor, and a controller. During operation, the switch controls an amount of current through the load. The current monitor samples a magnitude of the current through the load, a magnitude of which varies over time during a time duration. Based on integrating the sample magnitudes of the current through the load over the time duration, the current monitor produces a current sense value. The current sense value is representative of an amount of current through the load. The controller controls an operational state of the switch based upon a comparison of the current sense value with respect to an over-current threshold value. For example, in response to detecting a condition in which the current sense value is greater than the overcurrent threshold value, the controller turns OFF (deactivates) the switch, reducing or eliminating delivery of current through the load.

Methods and apparatus for determining the root-mean-square (RMS) voltage of an input voltage are provided herein. In some embodiments, an apparatus for determining the root-mean-square (RMS) voltage of an input voltage includes an amplifier to modify an amplitude of the input voltage signal; an amplitude detector, coupled to the amplifier, to transform the spectrum of the modified input voltage signal so that an increased portion of the signal is disposed within a desired frequency region; and a root-mean-square (RMS) converter, coupled to the amplitude detector, to determine the RMS voltage of the transformed input voltage signal, wherein a bandwidth of the RMS converter includes the desired frequency region.

Methods and apparatus for determining the root-mean-square (RMS) voltage of an input voltage are provided herein. In some embodiments, an apparatus for determining the root-mean-square (RMS) voltage of an input voltage includes an amplifier to modify an amplitude of the input voltage signal; an amplitude detector, coupled to the amplifier, to transform the spectrum of the modified input voltage signal so that an increased portion of the signal is disposed within a desired frequency region; and a root-mean-square (RMS) converter, coupled to the amplitude detector, to determine the RMS voltage of the transformed input voltage signal, wherein a bandwidth of the RMS converter includes the desired frequency region.

Systems, methods, and computer program products for sinusoidal nulling are provided. Aspects include transmitting, by a controller, an excitation signal to a first sensor, determining, by the controller, a target harmonic based at least on one or more characteristics of the excitation signal, receiving a return signal from the first sensor, sampling the return signal at a first sample rate based on the target harmonic, and adjusting a phase of the sampled return signal to null the target harmonic amplitude to form an adjusted return signal.

Systems, methods, and computer program products for sinusoidal nulling are provided. Aspects include transmitting, by a controller, an excitation signal to a first sensor, determining, by the controller, a target harmonic based at least on one or more characteristics of the excitation signal, receiving a return signal from the first sensor, sampling the return signal at a first sample rate based on the target harmonic, and adjusting a phase of the sampled return signal to null the target harmonic amplitude to form an adjusted return signal.

An example log power detector includes a gain or attenuation circuit and a detector circuit. The gain or attenuation circuit includes a plurality of gain or attenuation elements arranged in a sequence, each gain or attenuation element configured to generate an output signal that is an amplified or attenuated version of an input signal provided thereto. The detector circuit includes a plurality of detectors, each detector configured to receive the output signal from a different one of the gain or attenuation elements and to generate a signal indicative of a power of the received output signal. At least the last detector is configured to receive a DC offset signal that is different from a DC offset signal received by at least one other detector. Such a log detector may provide effective noise compensation to reduce errors caused by input noise, especially for low-power and/or high-frequency input signals.

An embodiment provides a method for measuring a component of an aqueous sample using square wave voltammetry, including: introducing the aqueous sample to a chamber of a square wave voltammetry apparatus; applying a stimulus voltage step to the aqueous sample, wherein the stimulus voltage comprises a staircase voltage, wherein each step of the staircase voltage defines a group and comprises two or more repeated square wave modulations of equal voltage amplitude; measuring a resultant current output resulting from the stimulus voltage, wherein the measuring comprises square wave voltammetry; and averaging the resultant current output across at least two or more cycles of each group. Other aspects are described and claimed.

An embodiment provides a method for measuring a component of an aqueous sample using square wave voltammetry, including: introducing the aqueous sample to a chamber of a square wave voltammetry apparatus; applying a stimulus voltage step to the aqueous sample, wherein the stimulus voltage comprises a staircase voltage, wherein each step of the staircase voltage defines a group and comprises two or more repeated square wave modulations of equal voltage amplitude; measuring a resultant current output resulting from the stimulus voltage, wherein the measuring comprises square wave voltammetry; and averaging the resultant current output across at least two or more cycles of each group. Other aspects are described and claimed.

In one example, an arc fault circuit interrupter (AFCI) is provided. The AFCI may include a plurality of current arc signature detection blocks configured to output a plurality of corresponding current arc signatures, and a processor. The processor may be configured to receive each of the plurality of current arc signature from each of plurality of current arc signature detection blocks, respectively, and generate a first trigger signal. The processor may be further configured to assess each of the current arc signatures, determine whether an arc fault exists based on the assessment, and generate the first trigger signal if an arc fault is determined to exist. A method for detecting an arc fault is also provided.