System and method for frequency measurement based on quadratic forms

摘要

A system and methods for determining points for an algorithm to calculate the frequency of a waveform measured from a monitoring device. Data points are measured from the waveform. A last point of interest from the previous cycle of the waveform is referenced. Four points of interest at equally spaced phase angles from the current cycle of the waveform are determined by calculating the average of the data points around each of the respective equally spaced phase angles of the current cycle of the waveform. The average value of the points of interest in the current cycle is subtracted from the four points of interest and the last point of interest from the previous cycle to compensate for DC bias. A frequency of the waveform is determined based on the determined four points of interest of the current cycle and the last point of interest from the previous cycle. The correction factor for determining sample frequency may be reduced for subsequent cycles in order to increase stability.