High precision phase measurement using reduced sine and cosine tables

A high-precision phase measurement technique, which can accurately determine the phase even when the signals are distorted by harmonics, was presented previously by the author (ibid., vol.38, p.954-60, Oct. 1989). He proposes a microprocessor-based hardware implementation of the technique. The hardware implementation requires two reduced tables: a sine table and a cosine table. If each table has i(i+5)/2 entries, then the phase can be accurately determined even if the signals are distorted by any number of harmonics in the range of second through ith harmonics