Patent Document ID: 4607218
Application ID: 06584770
Patent Flag: 1

Claim One:
1. A method for digital measurement of the phase difference (F) between two cyclic and periodic signals (U,V) having the same frequency comprising the steps of; providing a timing signal (T) having a frequency much higher than the frequency of either of said signals (U,V); counting the cycles of said timing signal (T) in an internal corresponding to said phase difference (F) by starting to count said timing signal cycles at a zero passage (T1) of one (U) of said two signals (U,V) in a predetermined direction and ending said counting upon the next succeeding zero passage (T2) of the other of said two signals (V) in the same said predetermined direction; using the number of said counted cycles in said phase difference interval to produce a first signal (Mi); counting the cycles of said timing signal (T) in an interval corresponding to the period (P) if one of said signals (U) by starting to count said timing signal cycles at a zero passage (T1) of one (U) of said two signals in a predetermined direction and ending said counting upon the next succeeding zero passage (T3) of said same one (U) of said two signals (U,V) in said same predetermined direction; producing a calibration signal (Ci) using the number of said counted cycles in said period interval; averaging a number (n) of said first signals (Mi); and determining said phase difference (F) using said number (n) of said first signals (Mi) and said calibration signal (Ci).