| 摘要 |
PURPOSE:To automate the eye pattern aperture evaluation of a digital signal containing a multilevel signal. CONSTITUTION:A sampling circuit 11 samples a specific time slot section of a digital signal S1 and generates sampling data S3. This data S3 is divided into plural levels by a level discriminating circuit 12 and becomes level discrimination data S4. This level discrimination data S4 is counted at every level and becomes counting data S5 by a counter circuit 13. When the digital signal S1 of the prescribed number of bits is inputted to this device, a CPU 2 calculates a standard deviation of the counting data S5 within a specific level range, and evaluates eye pattern aperture of the digital signal S1 from this standard deviation. |
