Automatic monitoring of digital communication channel conditions usinhg eye patterns

A digital signal transmission channel monitor for determining in real-time degradation in transmission quality created by stress in a digital transmission system, comprising, a degradation detector having means for generating an eye pattern's analog signal for a received data signal and applying that eye pattern signal to a grid containing a number of cells, the cells being located within boundaries of an undistorted eye pattern having maximum and minimum voltage amplitude values and a time period T, a number of the cells being identified with a predetermined, generalized error region with all of the cells being formed by predetermined voltage amplitude levels located between the maximum and minimum voltage amplitude values and by predetermined time periods within said time period T, the detector further comprising means for determining when an eye trace of the generated eye pattern's analog signal is located within particular cells, means for obtaining the number of times an eye trace is in each cell of the grid during a predetermined period of time, the numbers from all cells being applied to a complex integrator containing a weighted summer having predetermined weights for each cell and which provides means for performing a weighted integration of said numbers, the complex integrator having means for transforming said weighted integration to obtain a test statistic, said detector having means for comparing said test statistic with a predetermined threshold value and means for indicating a stress condition when said test statistic exceeds said predetermined threshold value during said predetermined period of time.