| 摘要 |
PURPOSE:To detect the shift of center phase without using an expensive measurement instrument of high frequency band area by generating a test data train in which the period of, at least, one data is shifted against an input data train having a prescribed period. CONSTITUTION:The first test pattern A in which one of data advances by t minutes by a control circuit 75 and the second test pattern B in which one of the data is delayed by t minutes by the next control clock CCL. At a continuity/discontinuity detecting part 8, a period detecting circuit 80 counts the period of each discriminating data of a discriminating data train and when a short period (or a long period) except a prescribed period is detected, a discontinuity identification signal DS is generated. And when the discontinuity of the discriminating data train against the test pattern A, a light emitting element 83 is lightened and in contrast with this, when the discontinuity of the discriminating data train against the test pattern B, a light emitting element 84 is lightened and when the discriminating data is continued, neither of light emitting elements 83 nor 84 is lightened. |
