Patent ID: 7083101

Claim:
A bar-code reader that scans a bar code that is formed by black bars and white bars having a width number in integral multiples of a basic width, and reads information that is indicated by the bar code scan result, comprising: a main controller; a mirror driving unit that receives a control signal from said main controller and rotates a polygon mirror; a laser diode driving unit that receives the control signal from said main controller for operating a laser diode to emit a laser beam to the polygon mirror; an A/D converter that converts an analog electric signal received from a bar code to a digital signal, said bar code receiving the laser beam reflected on the polygon mirror; a band-limiting differential processing unit that receives the digital signal from said A/D converter; a basic-width calculating unit that calculates a basic width based on the digital signal from said A/D converter; a decoding unit that carries out sampling operation, using band-limiting differential data output from said band-limiting differential processing unit and the basic width output from said basic-width calculating unit, so as to obtain a peak value of amplitude of said band-limiting differential data and convert the thus obtained peak value to a character data; and a communication interface that receives the character data from said decoding unit by way of said main controller and transmits the data to a POS terminal residing outside the bar-code reader.