PURPOSE: To eliminate the need for shortening a repeated period of a clock signal, and to detect effectively an abnormal pattern having minute width or length, by expanding the width of a binary-coded signal of specified width or less, and thereafter, quantizing it.
CONSTITUTION: A binary-coded signal from a signal input terminal 6 is inputted to the first pulse signal generating circuit 7 and an OR circuit 8 of the first block, and the second pulse signal generating circuit 11 and an AND circuit 12 of the second block. By this first block, only width d1 in width d1, d2 smaller than a repeated period γ of the binary-coded signal is expanded to width (t). Subsequently, by the second block, width d2 is expanded to width (t), and outputs of the respective circuits 8, 12 are given to shift registers 13, 14. Subsequently, a clock from a clock signal generating circuit 9 is given to the registers 13, 14, and an abnormal pattern having minute width or length is detected effectively without shortening a repeated period of a clock signal.
MITA KIKUO
ANDOU MORITOSHI
