| 摘要 |
PURPOSE:To constantly obtain a proper slice level by following a slice level to an original signal with respect to a base material part to be detected and reducing the slice level with a constant coefficient with respect to a pattern part to be detected. CONSTITUTION:A pattern detecting signal and the slice level from a buffer 19 are compared in a comparator 20 to output a binarization signal and a switch 11 is opened and closed according to this signal. In the base material part to be detected, the output of the comparator 20 goes to a low level to turn on the switch 11 and time constant circuits 12, 13 are charged, so that the output of a buffer 15 is substantially similar to the original signal and said slice level follows the original signal. In the pattern part to be detected, the output of the comparator 20 goes to a high level to turn off the switch 11, an electric charge stored in the tie constant circuits 12, 13 is discharged, the output of the buffer 15 is gradually reduced, so that said slice level is reduced with the constant coefficient. |
