| 摘要 |
<p>A signal processing circuit includes: a signal input unit (30) for optically detecting a bar code and outputting a first signal; a differential unit (D) connected to the signal input unit (30), for amplifying the first signal, differentiating the first signal, filtering the first signal and outputting a second signal; a comparison unit (C) connected to the differential unit (D), for integrating the second signal and outputting a third signal, and comparing the second signal with the third signal and outputting a fourth signal; a slice level generation unit (S) connected to the differential unit (D), for holding a peak voltage of the second signal; a gate signal output unit (G) connected to the differential unit (D) and the slice level generation unit (S), for comparing the second signal with the positive slice voltage and the negative slice voltage; and a signal output unit (OUT) connected to the comparison unit (C) and the gate signal output unit (G), for inputting the fourth signal and the positive slice voltage, and outputting a gate signal to obtain a binary-coded signal.</p> |
