Two-dimensional pattern digitizer

摘要

A digitizer includes a reference level generator for generating a reference level, a comparator for comparing a signal level of the analog input with the reference level to provide a digitized output, a first detecting circuit for detecting a moderate change in the signal level of the analog input so as to change the reference level in accordance with the detected moderate change in the signal level of the analog input, and a second detecting circuit for detecting a rapid change in the signal level of the analog input so as to change the reference level in accordance with the detected rapid change in the signal level of the analog input.