Abstract: A system and method for improving the ability of an electronic meter to make measurements on signals to determine content of different frequencies, and harmonics of the fundamental frequency, of AC signals (voltages and currents). The line frequency is determined and compensated for prior to performing frequency-dependent parameter measurements or determining frequency-dependent parameters.
Type:
Grant
Filed:
November 30, 1998
Date of Patent:
October 3, 2000
Assignee:
ABB Power T&D Company Inc.
Inventors:
Rodney C. Hemminger, Scott T. Holdsclaw, Vick A. Hubbard
Abstract: A device for detecting a voltage of an individual unit cell included in a combination battery consisting of a number of unit cells connected in series. The unit cells are divided into several groups, and a voltage divider circuit having a cell-side resistor and a reference-side resistor is connected to each unit cell. A divided potential of each unit cell is supplied to a cell voltage detector from each voltage divider circuit. Also, a reference potential that is common to a cell group is supplied to the detector from a junction connecting two neighboring cell groups. The cell voltage detector determines the voltage of each unit cell, group by group, based on a difference between the divided potential and the reference potential. Since the reference potential is common to all the voltage divider circuits in one cell group, the voltage divider circuits can be simplified.
Abstract: A self-framing serial trigger within an oscilloscope or specialized analyzer construes an absence of the data's clock signal for at least a selected length of time as implying the occurrence of a framing signal. This frees the serial trigger from otherwise needing an externally supplied framing signal. The serial trigger may include a shift register containing the most recent N-bits of the data, which is then bit-wise compared to the trigger pattern (stored in a register). This level of comparison may provide for don't care bits in the trigger pattern. The results of this bit-wise comparison are then inspected for a certain uniformity indicating that the trigger pattern has been matched. An additional circuit may count clock signals since the last implied framing pulse. If this additional count has not yet reached M (or counted down from M to zero) the match is premature, and no trigger signal is generated.