Guide Technology, Inc.

Mordechai Ben-Zeev

Sassan Tabatabaei

Michael Lee

Paul Frederick Miller

A system and related method for generating a test signal with controllable amounts of signal jitter includes a pattern generator, a programmable arbitrary waveform generator (AWG) and a phase modulator. The pattern generator is configured to generate a data signal characterized by a given data pattern, bit rate and pattern length. A trigger signal representative of initial timing information associated with the data signal is provided to the AWG which subsequently generates a modulation signal with a frequency equal to the bit rate divided by the pattern length of the data signal. This modulation signal is provided to the phase modulator, along with a reference clock signal, and the phase modulator generates a modulated clock signal controlled by a phase modulation means (e.g., a controllable delay line) fed by the modulation signal. The resultant jittery clock signal is then provided to the pattern generator to adjust the timing of the data signal and to generate a signal representative of a data signal with data-dependent jitter characteristics. Additional inputs to the delay line of the pulse generator may include a random Gaussian noise signal for providing random jitter and a periodic signal for providing periodic jitter.

System and method of generating test signals with injected data-dependent jitter (DDJ)

Methods for estimating data-dependent jitter (DDJ) from measured samples of a transmitted data signal include a first exemplary step of obtaining a plurality of measurements (e.g., time tags and event counts for selected pulse widths in the data signal). Such measurements may be obtained at predetermined intervals within a transmitted signal or may be obtained at randomly selected intervals, and should yield measurements for each data pulse in a repeating data pattern. An average unit interval value representative of the average bit time of the transmitted signal is determined. Time interval error estimates representative of the timing deviation from each signal edge's measured value relative to its ideal value (determined in part from the calculated average unit interval value) are also determined, as well as a classification for each measured signal edge relative to a corresponding data pulse in the repeating data pattern. DDJ delta lines are then calculated for signal edges of each pulse width in the transmitted data pattern, from which peak-to-peak DDJ values and/or estimates of duty-cycle-distortion (DCD) can be determined.

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Mordechai Ben-Zeev