Abstract: A count processor counts a zero crossing detection count C. A fraction processor for calculating a fraction Fj (j=1 to L) of the zero crossing detection count on the basis of the digital signal at sampling timings immediately before a zero crossing specifying and when the zero crossing specifying, and computing a fraction processing parameter Gj=Nj?Fj using a zero crossing detection number Nj(0?Nj?N?1) in a period corresponding to a sampling count N necessary for averaging determined in advance. The averaging is performed according to the following formula, where C is the output of the count processor at the end of an averaging period and Gj (j=1 to L) is L fraction processing parameters (L indicates the number of Gj included between the averaging counts N) computed by the fraction processor, and the phase of the digital signal is computed, whereby the phase is calculated on the basis of an input signal digital value obtained by an AD converter.

Abstract: The inventive phase measuring device includes a first A/D converter 2 that digitizes a first periodical input signal X at each predetermined sampling timing and outputs the resultant signal as a digital signal Xd, a first zero-crossing identification means operable to detect a sign of Xd, a counting processing unit 4 that counts a difference in the number of times of zero-crossing detection by the first zero-crossing identification means and calculates the difference at each sampling timing, and a fraction processing unit 5 that computes a fraction of the number of times of zero-crossing detection on the basis of Xd at sampling timings immediately before and immediately after determination of zero-crossing by the first zero-crossing identification means. An averaging processing unit 6 performs averaging by adding up and totalizing the outputs from the counting processing unit 4 and the fraction processing unit 5, thereby computing a phase.

Abstract: This phase measurement device is provided with: a count processor 4 that counts a zero crossing detection count C, which is the number of times a change in the sign of a digital signal has been detected; and a fraction processor 5 for calculating a fraction Fj (j=1 to L) of the zero crossing detection count on the basis of the digital signal at sampling timings immediately before and immediately after a zero crossing specification means has determined a zero crossing, and computing a fraction processing parameter Gj=Nj?Fj using a zero crossing detection number Nj (1?Nj?N) in a period corresponding to a sampling count N necessary for averaging determined in advance.

Abstract: The inventive phase measuring device includes a first A/D converter 2 that digitizes a first periodical input signal X at each predetermined sampling timing and outputs the resultant signal as a digital signal Xd, a first zero-crossing identification means operable to detect a sign of Xd, a counting processing unit 4 that counts a difference in the number of times of zero-crossing detection by the first zero-crossing identification means and calculates the difference at each sampling timing, and a fraction processing unit 5 that computes a fraction of the number of times of zero-crossing detection on the basis of Xd at sampling timings immediately before and immediately after determination of zero-crossing by the first zero-crossing identification means. An averaging processing unit 6 performs averaging by adding up and totalizing the outputs from the counting processing unit 4 and the fraction processing unit 5, thereby computing a phase.