Patent Document ID: 5477472
Application ID: 08355749
Patent Flag: 1

Claim One:
1. A method of synthesizing a square wave from a cyclical signal subject to noise and to varying peak and valley amplitudes comprising the steps of: establishing a large and a small hysteresis value; producing a digital signal from the cyclical signal; identifying peaks and valleys of successive half cycles in the digital signal; setting first reference levels at a small hysteresis value above each valley and below each peak; setting second reference levels at a large hysteresis value above each valley and below each peak; and generating a digital square wave transition for each half cycle by: selecting the first reference level when and only when, for the previous half cycle, the signal crossed the second reference level, otherwise selecting the second reference level; and in the current half cycle, generating a transition after the signal passes a peak or valley and then passes the selected reference level, whereby noise is rejected due the large hysteresis value, and single cycle anomalies caused by a low half cycle amplitude are accepted as valid due to the small hysteresis value.