Eye-Diagram Measurement of High-Speed Digital Signals using Sampling Oscilloscope with Time-Base Correction

In this paper, we investigate the signal processing method of time-base correction for a sampling oscilloscope, so that the eye diagram of a high-speed digital signal can be accurately characterized under different measurement modes. To achieve precise synchronization, a single 12-GHz microwave reference signal is used not only as the clock of pattern generator for generating the pseudo-random binary sequence (PRBS), but also to provide two quadrature sinusoidal waves needed by sampling oscilloscope time-base correction. In the oscilloscope measurement mode, free-run trigger is utilized to randomize the time base which is reconstructed from quadrature sinusoidal measurements, and eye diagram is extracted from the noise-like raw PRBS measurements. In the eye/mask measurement mode, the distortion of time base is estimated and corrected according to quadrature sinusoidal measurements, and the performance of eye-diagram characterization is improved.