| 摘要 |
<p>In an optical code sensor of the type in which a signal derived from a light beam encoded with digital data is obtained by extracting transitions, an adjustable bandwidth filter is interposed before processing to extract the data. The distance of the optical code is detected, and the filter bandwidth is increased in relationship to the distance of the bar code. Preferably, the input signal to the filter is applied to a shift register and the output at each stage of the register is multiplied by a predetermined coefficient calculated to achieve a particular waveshape, preferably a Gaussian waveshape, via the entire set of coefficients. The register stage outputs, multiplied by the coefficients are then added together to produce a filtered output signal applied to the processor.</p> |
