| 摘要 |
PROBLEM TO BE SOLVED: To prevent degradation of a error rate characteristic by extracting digital data of a cross point part and a cross point continuous data part of an eye pattern from an output of an A/D converter, generating integrated voltage by integrating it, applying it to an input side of the A/D converter and suppressing the dispersion of input offset voltage of the A/D converter. SOLUTION: Analog data that are inputted to an A/D converter 11 are converted into (n) system digital data and an optical one bit is taken out among (n) system output data by using two frequency division clock which divides an output of an oscillator 10 two frequencies. An arbitrary one bit sequentially fetches the most significant bit of output data that correspond to a cross point part of an eye pattern and a cross point continuous data part by using a flip- flop 13, inverts it and sends it to an integrating circuit 14. Each time the inverted most significant bit is inputted, the circuit 14 integrates it and sends integrated voltage as control voltage to a D terminal of the converter 11. |
