Method and device for the evaluation of the margin of safety of a video signal, 1984,

摘要

The evaluation of the safety margin, makes it possible to carry out of the tools of test pieces of equipment of digital television. The device is placed on a digital interface parallel. It comprises: an input interface 10, means 12 for generating, from the clock signal the output of the input interface, a reference clock signal (h ref or h - 1 and ref) having a fixed phase shift compensates for that caused by the input interface and a clock signal of the test (test h - 1 / 2) having a phase shift that can be selected, at least two registers of decoding, 20, 22 receiving the data signal and of the clock inputs respectively receive the reference clock signal and the clock signal of a test, a comparator 24 connected to the output of the two registers and supplying an output signal in the case of a difference, and management means making it possible to increase progressively the amplitude of the phase shift that can be selected and to indicate, for each phase shift, the existence of not matchings.