Method of estimating phase noise spectral density and jitter in a periodic signal

摘要

A method of estimating phase noise spectral density from a jitter versus time vector array obtained from a periodic signal having an average frequency includes the an initial step of converting the jitter verus time vector array to a phase error versus time vector array using an estimate of the average frequency of the periodic signal. A time to frequency transform is applied to the phase error versus time vector array to generate a phase error magnitude versus frequency vector array, and a phase noise spectral density vector array obtained by normalizing the phase error magnitude versus time vector array to a one hertz bandwidth. The method of estimating the jitter in the periodic signal includes the steps of generating a vector array of estimated reference crossing times of the periodic signal in the waveform record using interpolation and calculating an estimated periodic signal frequency based on a selected number of reference crossings in the estimated reference crossing times vector array and associated time positions of the waveform samples from the first selected reference crossing to the last selected reference crossing in the waveform record. A vector array of uniformly spaced ideal reference crossing times is generated based on the estimated periodic signal frequency, and a uniformly spaced jitter versus time vector array is generated by determining the difference between the ideal reference crossing times and the corresponding estimated reference crossing times of the periodic signal.