An electronic device is provided. The electronic device includes a panel, a detection system, and a test loop. The test loop is electrically connected to the panel and the detection system. The detection system includes a detection unit and a controller. The detection unit detects a signal transmitted by the test loop, and provides a detection result to the controller.

Systems and methods are provided for improving the operation of a computer or other electronic device that utilizes root-mean-square (RMS) measurements, e.g., RMS current measurements, by reducing error in the RMS measurement. A series of measurement samples are received at a processor, which executes a noise-decorrelated RMS algorithm including: calculating a current-squared value for each measurement sample by multiplying the measurement sample by a prior measurement sample in the series (rather by simply squaring each measurement sample as in conventional techniques), summing the current-squared values, and calculating an RMS value based on the summed values. The processor may also execute a frequency-dependent magnitude correction filter to correct for frequency-dependent attenuation associated with the noise-decorrelated RMS algorithm. The calculated RMS value has a reduced error, particularly for lower-end current measurements, which may improve the operation of the computer or electronic device that utilizes the RMS value.

A current monitor circuit includes a sense resistor coupled to a direct current (DC) power supply to sense a current signal, an operational amplifier (op-amp) coupled to the sense resistor to sense a voltage developed across the sense resistor, and a low-pass filter coupled to the op-amp and an analog-to-digital converter (ADC). The low-pass filter reduces aliasing due to out-of-band signal content. The current monitor circuit is coupled to the ADC to provide real-time measurements of power supply load current as input to an active power management (APM) firmware.

In some embodiments, a threshold calibration system to provide a zero voltage switching signal is presented. The system includes a divider coupled to a switching node; a calibration ramp generator; a reference voltage generator; a comparator; a first multiplexer coupled to receive a divider output signal from the divider and a calibration ramp signal from the calibration ramp generator and provide a signal to the comparator based on a calibration enable signal; a second multiplexer coupled to receive reference voltages from the reference voltage generator, the second multiplexer provided a threshold signal to the comparator; and a digital feedback circuit receiving an output signal from the comparator and providing the zero voltage switching signal.

A current sensing circuit includes a current sense amplifier and a correction circuit. The current sense amplifier has an offset voltage. The correction circuit is configured to evaluate the offset voltage of the current sense amplifier. The correction circuit is further configured to issue a correction signal to the current sense amplifier based upon the evaluated offset voltage. The correction signal is to adjust the offset voltage.

A switched mode power supply including an alternating current power supply configured to output a voltage, a sense resistor configured to sense a voltage output from the power supply, a current sense processor configured to sense a current level through the sense resistor, sense disturbances in the sensed voltage, and reconstruct the sensed voltage to eliminate the disturbances.

An electrical energy meter includes an A/D converter and a processing circuit. The A/D converter is configured to generate digital samples of voltage and current waveforms in a polyphase electrical system. The processing circuit is operably coupled to receive the digital samples from the A/D converter and to integrate over time at least one digital sample multiple times to produce a filtered value from which harmonic distortion has been removed, identify a fundamental frequency only electrical parameter measurement for the polyphase electrical system with reference to the filtered value, and store the identified fundamental frequency only electrical parameter measurement in a data store.

An electrically conductive probe, such as a probe similar to those utilized in other electric leak detection systems, is positioned electrically adjacent to different regions of a wall of an underground access chamber, for detection of leaks therein. In one embodiment, the probe is positioned at an elevation and circumferential position which is sequentially adjusted so that the probe can scan regions of the wall for leaks. In another embodiment, a modified probe remains centrally located within the underground access chamber and only moved vertically. The modified probe is fitted with whiskers extending radially. The modified probe includes sectors circumferentially spaced from each other and with each whisker associated with one of the sectors. A selector switch electrically connects one sector to the electrically conductive cable. Data collected by either probe can be graphed or otherwise analyzed with regions of high conductivity correlating with leaks in the underground access chamber.

Systems and methods are provided for improving the operation of a computer or other electronic device that utilizes root-mean-square (RMS) measurements, e.g., RMS current measurements, by reducing error in the RMS measurement. A series of measurement samples are received at a processor, which executes a noise-decorrelated RMS algorithm including: calculating a current-squared value for each measurement sample by multiplying the measurement sample by a prior measurement sample in the series (rather by simply squaring each measurement sample as in conventional techniques), summing the current-squared values, and calculating an RMS value based on the summed values. The processor may also execute a frequency-dependent magnitude correction filter to correct for frequency-dependent attenuation associated with the noise-decorrelated RMS algorithm. The calculated RMS value has a reduced error, particularly for lower-end current measurements, which may improve the operation of the computer or electronic device that utilizes the RMS value.

A method of obtaining characteristic measurements K and of an electrical system comprising at least two terminals, the method comprising: injecting a reference voltage at a first of the at least two terminals; measuring a voltage at a second of the at least two terminals to provide a measured voltage, the second terminal being connected to earth; measuring a ratio of amplitude between the injected reference voltage and the measured voltage to provide a K value; and measuring a phase angle difference between the injected reference voltage and the measured voltage to provide an angle value .