The present invention is a method and an apparatus for measuring phase differences between signals A and B using an absolute voltage value for each phase difference between ±180°. This is accomplished using a third signal C, which is a signal having a phase approximately equal to the average phase between signals A and B. Signals C and A are subsequently amplitude limited and mixed to produce a fourth signal D, which is a signal having associated an absolute voltage value for each degree of phase difference between ±180° for signals A and B.