| 摘要 |
<p>PURPOSE:To always ensure the accurate reading regardless of a change of scanning speed, by deciding a character from combinations of 9 types of major sorted signals which are obtained by comparing the width value ratio calculated from a bar code signal with the width of said bar code signal. CONSTITUTION:A pulse width detecting circuit 14 receives an output instruction by the detection of a left bar and then writes the values of a counter 14a successively to registers A-D. The data of a C register 19c is doubled bya multiplier circuit 21 to be written to a register 23a and then multiplied by 0.5 times to be written to a register 23b respectively. So is with a D register 19d. Comparators 20a and 20b decide the data on white or black bar regions of the same type and feed the result of decision to a width decoder 25. The decoder 25 delivers 9 types of major sorted signals S1-S9 from combinations of decision result signals d1-d6. At the same time, the ratio calculation results given from comparators 27a-27e are fed to a decoder 26. The decoder 26 recognizes the bar code.</p> |
