| 摘要 |
PURPOSE:To measure automatically an effective eye aperture rate by applying A/D conversion to a sample-hold value, extracting the absolute value, classifying it into 1 signal and 0 signal and obtaining a percentage of a ratio of a difference of a minimum value of 1 signal and a maximum value of 0 signal at an optional time to a proper peak value of an equalizer output. CONSTITUTION:A classifying circuit 3 compares a prescribed value of threshold value inputted externally with an output signal of an A/D converter circuit 2, classifies the result into 1 and 0 signals, the 0 signal is fed to a maximum value detecting circuit 4 and the 1 signal is fed to a mimimum value detecting circuit 5. The maximum value detection circuit 4 obtains a maximum value among 0 signals fed from the circuit 3 within a specified time and similarly, the minimum value detection circuit 5 obtains a minimum value among 1 signals fed from the circuit 3 within the same time and the result is given to the calculation circuit 6. The calculation circuit 6 calculates a difference between the minimum value and the maximum value to obtain a percentage of a ratio of the (x) to the proper peak value VO-P. It is outputted as an effective eye aperture rate. |
