| 摘要 |
PURPOSE:To reduce the time for waveform check by obtaining a signal representing the end of the reading of a specific eye pattern of a compact disk and by using the said signal to stop writing in a waveform recorder and writing the waveform data alone in a memory. CONSTITUTION:A comparator 1 of an eye pattern detection circuit compares a signal from a compact disk with a reference voltage Vs and the result of comparison controls the count of clock of the 1st counter 2. Further, an output of the counter 2 is received by the 1st FF 3 and when a borrow signal comes, the output Q is brought into an H level and inputted to the 2nd counter 4 and a gate 6. the borrow signal of the counter 4 resets the FF 3 and the gate 6 ANDs the output of the comparator 1 and the output Q of the FF 3 and its output is fed to the 2nd FF 7 as the clock input. Then the signal representing the end of the specific eye pattern is obtained to reduce the waveform check time.
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