| 摘要 |
PURPOSE:To read data by a reading sensor together with detection of the variation of positions and angles and to reduce the cost of a reading device, by providing a positioning reference line at the side of an optical recording medium and at the same time setting a detecting means for reference line at the side of the reading device. CONSTITUTION:A reading device for optical recording medium is mainly provided with a reading sensor 10 which reads data with follow-up to a track 4 in a data recording area 3, a binary coding circuit 20 which binary codes the output video signal of the sensor 10, a buffer 30 which stores temporarily the binar coded signal Bs, a reference line detecting means 40 which detects a reference line 5 from the signal Bs and a synchronizing signal generating circuit 50. The means 40 contains an AND gate circuit 41 as a signal level discriminating means to sample the high level part of the signal Bs delivered from the circuit 20 synchronously with the synchronizing signal phiR. Then the means 40 compares the count value delivered from a counter 42 with the time width set previously and delivers the reference line detecting signal Ls when the count value is larger than the set time width through a comparator 43 which serves as a deciding means.
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