| 摘要 |
<p>PURPOSE:To read exactly by outputting a start pulse, in case when scale factors of signal width corresponding to the sum total of a black bar and the next white space, and signal width corresponding to the preceding white space exceed a prescribed value. CONSTITUTION:Signal width Wwn corresponding to the part whose reflection factor is high, in an electric signal whose waveform has been shaped is compared in order with the sum of signal width Wbn correspondig to the next lower part, and sigal width Wwn+1 corresponding to the next higher part. When a scale factor of the signal width Wwn of the preceding high reflection factor part against the sum of signal width (Wbn+Wwn+1) exceeds a prescribed value, read by a bar code decoder 10' is started. In the subsequent sequential comparison, while the scale factor is smaller than the prescribed value, read is executed continuously until the time of its end. When the scale factor exceeds the prescribed value before said read ends, read before that time is cleared, new read is started immediately, and these operations are repeated.</p> |
