The device for detecting a leak may include: an earth voltage measuring unit measuring earth voltage; an ADC unit sampling the measured earth voltage and converting the sampled earth voltage into a digital value; an effective value calculating unit calculating an effective value of the earth voltage converted into the digital value; a Fourier transforming unit performing Fourier transform of the measured earth voltage to calculate voltage for each harmonic component; a content rate calculating unit calculating a voltage content rate of the fundamental frequency to voltage; a harmonic distortion rate calculating unit calculating a total harmonic distortion and a harmonic distortion factor based on the voltage for each harmonic component; a zero-crossing estimating unit estimating a zero-crossing count; and a suspicious earth leaking area determining unit determining that the earth voltage is generated by the leak of the AC commercial power.

A frequency adaptive harmonic current generator, including a microcontroller board (15) used for controlling the generation of harmonic currents and frequency adaptive operating function; an electronic relay (11) controlled and switched over the digital output of the microcontroller (21), the resistor (23) and the transistor (24); a data collection unit (13) to which the voltage divider (5), the buffer (6) and the current shunt (8) are connected for the measurement of voltage and current harmonics and which reads the current and voltage values and transfers such values to the panel type computer (14); and a panel type computer (14) which includes software for making, presenting and recording the measurements, the external connections of which are ensured by USB connectors (18) and a LAN connector (19), which displays the measurement values to the user, and which has push-button (20) for switching on/off operations.

A flux gate current sensor includes a magnetic core, a measurement winding, an excitation circuit arranged to generate a digital excitation signal, an acquisition circuit arranged to acquire an analog measurement voltage from the terminals of the measurement winding and to produce a digital measurement signal, a demagnetization servocontrol circuit arranged to use the digital measurement signal to produce a digital demagnetization signal for compensating magnetic flux produced by the current that is to be measured, a summing circuit arranged to sum the digital excitation signal and the digital demagnetization signal so as to obtain a digital injection signal, and an injection circuit arranged to produce an analog excitation current from the digital injection signal and to inject the analog excitation current into the measurement winding.

A flux gate current sensor includes a magnetic core, a measurement winding, an excitation circuit arranged to generate a digital excitation signal, an acquisition circuit arranged to acquire an analog measurement voltage from the terminals of the measurement winding and to produce a digital measurement signal, a demagnetization servocontrol circuit arranged to use the digital measurement signal to produce a digital demagnetization signal for compensating magnetic flux produced by the current that is to be measured, a summing circuit arranged to sum the digital excitation signal and the digital demagnetization signal so as to obtain a digital injection signal, and an injection circuit arranged to produce an analog excitation current from the digital injection signal and to inject the analog excitation current into the measurement winding.

According to methods of performing measurements to determine a distance to a passive-intermodulation (“PIM”) source, a first RF signal comprising a first frequency and a second RF signal comprising a second frequency may be applied to a device under test. A reference signal comprising a higher-order intermodulation-product of the first frequency and the second frequency may also be generated. An output signal from the device under test and the reference signal may be digitized and a calibration measurement may be applied. A phase difference between the device under test output and the reference signal may be determined. A plurality of phase differences may be determined for multiple first frequencies, and from the plurality of phase differences, a delay may be calculated, which may be multiplied by the velocity of propagation on the medium connecting the device under test to the test equipment to determine a distance to the PIM source.

According to methods of performing measurements to determine a distance to a passive-intermodulation (“PIM”) source, a first RF signal comprising a first frequency and a second RF signal comprising a second frequency may be applied to a device under test. A reference signal comprising a higher-order intermodulation-product of the first frequency and the second frequency may also be generated. An output signal from the device under test and the reference signal may be digitized and a calibration measurement may be applied. A phase difference between the device under test output and the reference signal may be determined. A plurality of phase differences may be determined for multiple first frequencies, and from the plurality of phase differences, a delay may be calculated, which may be multiplied by the velocity of propagation on the medium connecting the device under test to the test equipment to determine a distance to the PIM source.

Embodiments of this application disclose a signal processing method and a related apparatus, to estimate passive intermodulation (PIM) signal strength. The method in embodiments of this application includes: First downlink signal data corresponding to each of N cells in a preset bandwidth resource scheduling solution is obtained. Then, first characteristic data corresponding to each piece of the first downlink signal data is determined. Then, first passive intermodulation PIM signal strength corresponding to a first cell is determined based on a preset signal strength evaluation model and the first characteristic data corresponding to each of the N cells, to accurately estimate impact of the first PIM signal on the first cell.

An electrical measurement apparatus may include a bias voltage generator configured to generate and output a bias voltage, a bias probe coupled to the output of bias voltage generator configured to apply voltage bias to a first portion of an external circuit which may be subjected to environmental stresses such as vibration, temperature, humidity etc., a measurement probe configured to receive a second electrical signal from a second portion of the external circuit, and a control unit configured to control the bias voltage generator to generate different bias voltages, patterns, AC/DC etc., receive the second electrical signal from the measurement probe and cause the device to output a response in the second electrical signal to the time-domain discontinuity in the first electrical signal.

A method and a measurement system for determining the noise power of a device under test especially the exact noise power is provided. The measurement method comprises determining a sideband gain of a measurement system using a calibration unit, connecting a device under test to the measurement system, measuring a noise power of the device under test with a receiver and correcting the measured noise power with the determined system gain including a sideband gain.

A method and a measurement system for determining the noise power of a device under test especially the exact noise power is provided. The measurement method comprises determining a sideband gain of a measurement system using a calibration unit, connecting a device under test to the measurement system, measuring a noise power of the device under test with a receiver and correcting the measured noise power with the determined system gain including a sideband gain.