| 摘要 |
<p>A low power bar code detection circuit is provided. The detection circuit, because of the sensitivity of its internal amplifiers (4,6, 8), is capable of reading reflected bar code images even in high ambient light, for example, in sunlight. This sensitivity is accomplished by having a high gain of the photode- tected bar code signal by amplifying it with a transresistance preamplifier (4). The low power is accomplished by using a pulse-modulated light source (10) for producing reflected images and having intermediate amplifier stages (6) of the detection circuit conduct only at the peak amplitudes of the detected image signal.</p> |
