| 摘要 |
PURPOSE:To enable accurate and stable reading-in of bar code at all times, by assuming the interval with the clock corresponding to N-division of interval of bar code equally and reading the presence of bar code signal in the assumed interval. CONSTITUTION:The document 4 is moved toward E and it is scanned toward F with the bar code scanning means 5 consisting of light source, lenses and photo electric converters. In the clock generating means 6, the roller 6a turns and the clock signal having the frequency according to the moving speed is obtained at the output (e). For example, the frequency to divide eight equally the mark interval of the bar code 3 is obtained. The block 7 inputs the bar code scanning signal (d) and the clock signal (e) to output the waveform (f). The block 8 detects the change of 1 0 of the signal (f) and the signal (g) is produced from the pulse of the signal (d), and the block 9 counts the clock with the signal (f) and a signal in which the bar code is not at a given location is produced when the count value between pulse groups exceeds 8. |
