Patent attributes
A unique word that can be contained in transmittal data is to be accurately distinguished. A correlation detecting section 36 calculates correlations A through N between received data containing one of a plurality of unique words A through N and the unique words A through N respectively characteristic of the information transmission rates A through N. For the unique words A through N, the thresholds A through N are respectively set, and a formula distinguishing section 342, when a correlation i (i is one of A through N) is above a threshold i, a unique word i is contained in the received data, and supplies formula type data indicating that the received data have been generated at an information transmission rate i matching the unique word i. A threshold altering section 380, upon distinguishment of a unique word, performs alteration to reduce a value of the threshold i and enlarge values of other thresholds.
