Abstract: A probe for connecting a device under test to a measurement device that corrects for dc errors and noise generated by the current flowing through the ground shield of a transmission line used by the probe. The probe identifies a voltage drop in the ground preferably using an additional line between the device under test and the measurement device. The signal provided to the measurement device is corrected based on the identified voltage drop.

Abstract: Filter/protection units positioned along a fiber optic cable are tested. The fiber optic cable includes a metallic sheath surrounding the cable. A cable locating unit generates an electric signal. The metallic sheath conducts the electrical signal. The electric signal creates a voltage within the metallic sheath. The voltage level is below a specified flashover point or threshold of a normally operating filter/protector unit. As a result, any filter/protector units that are triggered by the electric signal are considered faulty.

Abstract: An electrical short-circuit detection device includes a first signal processing module for receiving a signal representative of an electrical current and supplying a first signal representative of the value of the electrical current and a second signal representative of the differential of the electrical current, and a second processing module for receiving the signals and comprising a short-circuit detection module for supplying a detection signal according to a curve overshoot. The second processing module monitors a limit curve overshoot and a ratio between variations of the signals. A short-circuit detection signal is supplied when the ratio exceeds a preset threshold. A circuit breaker incorporates such a device. The process comprises monitoring limit curve overshoot and the ratio between variations of the signals.

Abstract: An EMI testing scheme involves analyzing an analog input signal in frequency band segments. The input signal is passband filtered and digitally sampled before being converted to a complex analytic signal via a Hilbert transform filter and then transformed into a frequency domain signal via a Discrete Fourier Transform (DFT). Pre-stored frequency window filters are then applied to the frequency domain signal. The set of discrete filter sample points which form the window filters are designed such that particular frequency sub-bands of a desired bandwidth within the frequency segment are selected for EMI analysis. By applying different frequency window filters to the frequency domain signal, different frequency sub-bands are sequentially selected for analysis. An inverse DFT transforms the filtered signal back to the time domain, and the peak voltage of the time domain signal is compared with a threshold to determine whether EMI levels within the selected sub-band are acceptable.