| 摘要 |
<p>In a bar code sensing system for sensing a record medium carrying bar coded characters, each character is represented by a plurality of regions each having a first or second reflectivity and formed by one or a plurality of contiguous bars of said first or second reflectivity. A single optical sensor (40) provides a sense signal to a self-adjusting reference level circuit (42) which provides a reference level to a comparator (44) connected to the optical sensor (40), whereby data signals are provided to a controller (46). The controller (46) contains first and second timers (TM0, TM1) which are utilized to determine the number of bars in each sensed regions, and the end of each sensed character. <IMAGE> <IMAGE> <IMAGE></p> |
