Methodof monitoring suitability of a transmission path for transmission of digital data signals, and apparatus for use in carrying out the method

摘要

A transmission path is monitored for its suitability for transmission of digital data by transmitting over the transmission path a video test signal which includes a horizontal sync pulse and at least one half-cycle of a generally sinusoidal pulse occurring at a predetermined time after the sync pulse, the generally sinusoidal pulses being inverted in alternate lines or alternate fields of the video test signal. The signal received at the other end of the transmission path is displayed on an oscilloscope-type CRT device having its horizontal sweep triggered by the horizontal sync pulse, so as to superimpose the alternate generally sinusoidal pulses. The configuration of the generally eye-shaped area resulting from such superimposition depends on the suitability of the transmission path for transmission of digital data.