An electrical test device may include a power supply, a conductive probe element, and a spectral analysis block. The power supply may be connected to an external power source. The conductive probe element may be connected to the power supply and may be configured to be energized by the power supply. The probe element may be configured to be placed in contact with an electrical system under test and apply an input signal containing current for measuring at least one parameter of the electrical system. The spectral analysis block may be connected to the probe element and may be configured to receive an output signal from the electrical system in response to the application of the current to the electrical system. The spectral analysis block may be configured to analyze frequency spectra of the output signal and detect a broadband increase in energy of the frequency spectra above a predetermined energy threshold. The broadband increase in energy may be representative of the occurrence of arcing in the electrical system.

A wireless charging system is configured to charge one or more receiver devices simultaneously. The wireless charging system includes multiple coils that may be driven independently based on a feedback system with one or more feedback channels. One of the feedback channels may be demodulated communication signals from the one or more receiver devices. The demodulation may be performed by a communication demodulation circuit with configurable gain. The demodulated communication signals are processed for error correction at a bit level and a packet level, which improves accuracy despite presence of multiple receiver devices and noisy conditions.

A wireless charging system is configured to charge one or more receiver devices simultaneously. The wireless charging system includes multiple coils that may be driven independently based on a feedback system with one or more feedback channels. One of the feedback channels may be demodulated communication signals from the one or more receiver devices. The demodulation may be performed by a communication demodulation circuit with configurable gain. The demodulated communication signals are processed for error correction at a bit level and a packet level, which improves accuracy despite presence of multiple receiver devices and noisy conditions.

Described are systems and techniques for extracting frequency and voltage harmonic transients corresponding to individual load events. Such systems and techniques can be used to make electrical loads aware of the operation of other loads in an electric grid. Thus, awareness is achieved using information derived only from a utility voltage waveform at a load. Also described are systems and techniques for incorporating such awareness into load controllers which allows loads to autonomously meet system level objectives in addition to their individual requirements.

An arc detection circuit includes a current detector and arc determination unit. The current detector detects a current flowing through a transmission line which connects an electric power supply device and an electric power conversion circuit. The arc determination unit calculates, from a result of measurement of the current, an area of interest and an area for comparison. The area of interest is an area of a region of interest defined by a predetermined frequency range and predetermined time for determination. The area for comparison is an area of a portion in which detected strength exceeds a predetermined strength threshold in the region of interest. The arc determination unit determines an electric arc has occurred when a ratio between the area of interest and the area for comparison exceeds a predetermined area-ratio threshold.

A test and measurement instrument includes a first channel input for accepting a first input signal, a second channel input for accepting a second input signal, a spectrogram processor for producing a first spectrogram from the first input signal and for producing a second spectrogram from the second input signal, and a display for simultaneously showing the first spectrogram and the second spectrogram. Methods are also described.

A frequency detection circuit includes: a first signal source for outputting a first clock signal; a second signal source for outputting a second clock signal having the same frequency as but a different phase from those of the first clock signal; a first sample hold circuit for undersampling a reception signal using the first clock signal; a second sample hold circuit for undersampling the reception signal using the second clock signal; and a frequency calculating circuit for calculating the frequency of the reception signal using a phase difference between output signals of the first sample hold circuit and the second sample hold circuit.

A frequency detection circuit includes: a first signal source for outputting a first clock signal; a second signal source for outputting a second clock signal having the same frequency as but a different phase from those of the first clock signal; a first sample hold circuit for undersampling a reception signal using the first clock signal; a second sample hold circuit for undersampling the reception signal using the second clock signal; and a frequency calculating circuit for calculating the frequency of the reception signal using a phase difference between output signals of the first sample hold circuit and the second sample hold circuit.

Collect a full band capture spectral reading from a plurality of cable/fiber broadband network customer units (e.g., cable modems or equivalent optical units); for each of the cable/fiber broadband network customer units, construct an ideal spectral reading. For each of the cable/fiber broadband network customer units, subtract the ideal spectral reading from the full band capture spectral reading to obtain a resultant spectrum. For at least one of the cable/fiber broadband network customer units, identify a persistent deviation from zero in the resultant spectrum that does not match a known impairment type. Identify at least one new impairment type corresponding to the persistent deviation from zero. Remediation of the new impairment type can be carried out as appropriate, and/or a detection pattern can be deployed to identify future occurrences of the new impairment type.

Collect a full band capture spectral reading from a plurality of cable/fiber broadband network customer units (e.g., cable modems or equivalent optical units); for each of the cable/fiber broadband network customer units, construct an ideal spectral reading. For each of the cable/fiber broadband network customer units, subtract the ideal spectral reading from the full band capture spectral reading to obtain a resultant spectrum. For at least one of the cable/fiber broadband network customer units, identify a persistent deviation from zero in the resultant spectrum that does not match a known impairment type. Identify at least one new impairment type corresponding to the persistent deviation from zero. Remediation of the new impairment type can be carried out as appropriate, and/or a detection pattern can be deployed to identify future occurrences of the new impairment type.