Systems, methods, and circuits for determining a duty cycle of a periodic input signal are provided. A delay element is configured to delay the periodic input signal based on a digital control word. A digital circuit is configured to generate a first digital control word used to delay the periodic input signal a first amount of time corresponding to a period of the periodic input signal, generate a second digital control word used to delay the periodic input signal a second amount of time corresponding to a portion of the periodic input signal having a logic-level high value, and generate a third digital control word used to delay the periodic input signal a third amount of time corresponding to a portion of the periodic input signal having a logic-level low value. A controller is configured to determine the duty cycle based on the first, second, and third digital control words.

The invention is related to the field of measurement electronics and related to the measurement of complex transfer functions (e.g. of impedance), especially in the presence of large disturbances and for measuring of small changes of the characteristics of the object under test. The goals of the proposed invention are achieved by detuning of the excitation and reference signals, e.g. by adding incremental phase-shift to the excitation signal to generate the reference signal.

Approaches for testing phase rotators are provided. A circuit for testing phase rotators includes a compare element including a first input and a second input, wherein the compare element is configured to compare a first phase of a first signal provided at the first input to a second phase of a second signal provided at the second input. The circuit also includes a first test bus connected to the first input and a second test bus connected to the second input.

In order to ensure safe operation of a multi-phase system, even a system including a plurality of phases, a number of phase groups is provided, which comprises some of the phases, wherein phase currents of the number of phase groups are merged in a group node to form a group sum current and a group sum current measurement value of the group sum current is captured. The current measurement values belonging to the number of phase groups are summed up to form a group sum and the group sum is compared with the group sum current measurement value to validate the phase currents of the phases in order to ensure safe operation.

A method monitors an electrical energy supply network or a subnetwork of the energy supply network. Measurement values detected at at least two measurement points of the energy supply network or subnetwork are evaluated. More specifically, phase angle values are evaluated as the measurement values or phase angle values determined using the measurement values are evaluated. A check is carried out based on the phase angle values to determine whether the energy supply network or the subnetwork is operating synchronously, and, in the event of an asynchronism identified based on the phase angle values, an island identification signal to be generated.

A system and method for the wireless synchronization of a self-powered power sensor (SPPS) to a central controller for calculating a value of an electrical parameter. The method includes receiving from a central controller a message that includes timing information of the central controller time base; sampling at least an electrical signal respective of a powerline connected to an SPPS; estimating from the samples of the at least an electrical signal at least a first electrical parameter, where the at least a first electrical parameter is adjusted using the timing information; generating a packet; appending to the packet the estimated at least a first electrical parameter; and transmitting the packet to the central controller.

A method and apparatus to detect breaks in tracks and/or detect the presence of a vehicle, such as a train, in a monitored section of the track or rail. Embodiments of the present invention measure the change in track inductance associated with a track or rail break. Electrical shunts are connected between the rails at spaced-apart intervals (for example a shunt can be placed every mile). At least two different frequencies of alternating current are generated and fed into the segments of rail (for example at or near a mid-point between the shunts). If a rail break occurs, the total inductance of the rail at that segment will change. Using two or more frequencies allows a rail break to be differentiated from environmental rail-to-rail and rail-to-earth leakage.

Methods are described to provide a new and improved display of phase identification measurements in a three-phase power distribution network, that is easier and more intuitive to interpret and define tagging reference phase. A short sequence of individual phase measurements are displayed as dots inside a static phase attribute display circle. The 3 primary, 12 secondary, and 6 three-phase attributes are displayed around the outside of the phase circle. When using a touch screen Smartphone or Tablet display device, the user simply touches inside the phase circle to rotate the dots around the center of the phase circle, so they line up with the known conductor phase attribute. This rotation defines the tagging reference phase for the circuit.

Methods are described to provide a new and improved display of phase identification measurements in a three-phase power distribution network, that is easier and more intuitive to interpret and define tagging reference phase. A short sequence of individual phase measurements are displayed as dots inside a static phase attribute display circle. The 3 primary, 12 secondary, and 6 three-phase attributes are displayed around the outside of the phase circle. When using a touch screen Smartphone or Tablet display device, the user simply touches inside the phase circle to rotate the dots around the center of the phase circle, so they line up with the known conductor phase attribute. This rotation defines the tagging reference phase for the circuit.

A wireless phasing voltmeter transmitting two bits per second includes a reference unit using two audio frequency pulses per second to modulate a radio frequency carrier wave for simplex transmission of phase information to a field unit. The time between the two data bits is proportional to the phase difference between the reference voltage waveform and a first GPS-signal based waveform. The audio frequency of the two audio pulses representing the two data bits points to the frequency of the electric grid, rising when the grid frequency is faster and falling when the grid frequency is slower. A meter probe measures the phase angle of the field conductor against a second GPS generated waveform. Comparison yields the phase angle difference between the field conductor and the reference conductor. The radio frequency simplex data transmission perhaps using a cellphone data link, transmitting lower data rates is more reliable over greater distances.