Patent ID: 8355469
Filing Date: 2013-01-15
Classification: G01R,H04L

Abstract:
1. A flexible timebase for eye diagrams comprising: means for recovering a clock signal from an input digital data signal; means for processing the clock signal to produce a reference signal; means for asynchronously sampling the input digital data signal and the reference signal using a free running oscillator; and means for generating an eye pattern from the asynchronously sampled input digital data signal and reference signal; wherein the generating means comprises: means for obtaining time values from the asynchronously sampled reference signal; and means for accumulating the sampled input digital data signal to generate the eye pattern; and wherein the obtaining means comprises a digital phase-locked loop of the type having a phase detector for receiving the sampled reference signal at one input and providing an error signal at an output, having a loop filter for generating from the error signal a control signal for a numerical controlled oscillator, and having a loop feedback as another input to the phase detector.