Method for digital interpolation of a period of a three-phase analog signal

Abstract From the Canadian patent

The values of three components of an analog signal are compared with zero and in two's compared with one another. Each possible combination of the comparison result within the range of possible phase argument values of the analog signal, has correlated therewith a respective zone whereby there is formed a coarse interpolation of a period of the analog signal into phase zones. The components are digitized and there are selected the components having the smallest (X), the intermediate (Y) and the largest (Z) absolute value. There are formed the digital functions H = Y - X and K = Z-Y + X. Each possible combination (H, K) is correlated to a respective predetermined number of steps of the phase …