| 摘要 |
A device for reading data of optical card using a read sensor, the optical card having a data region in which data tracks are arranged in many number in parallel along a reference line. The device comprises a reference line detect unit that produces an average position signal of reference lines and a data clock generating unit that generates a data clock that serves as a reference when the data bits are being read out. The reference line detect unit comprises a reference line detect circuit, an output circuit for producing an average position signal of reference line, a timing comparator circuit which receives the output of the reference line detect circuit and the output of an output circuit and compares these two outputs, and an integration circuit which integrates the outputs of said timing comparator circuit and produces an output to said output circuit. The data clock generating unit comprises an oscillation circuit for producing clocks of a frequency N times as great as that of the data clocks that are generated, a frequency-dividing circuit which receives average position signals to divide the clocks from the oscillation circuit by N in synchronism with said average position signals to obtain data clocks, a pulse generating circuit which produces pulses at a position corresponding to a distance between the reference lines of data clocks with an average position as a reference, a timing comparator circuit which compares the timing of a detect signal of a reference line neighboring to the reference line with the timing of said pulse, and an integrating circuit that integrates the output of said timing comparator circuit and feeds the output back to the oscillation circuit to set the frequency. Such a device for reading the optical card of the invention makes it possible to obtain very accurate data clocks without requiring magnification adjustment of the optical system that was needed in the prior art. |
