Apparatus for and method of measuring cross-correlation coefficient between signals

Claim 1

An apparatus for measuring the cross-correlation coefficient between a first and a second signals under measurement comprising: a first timing jitter estimator for estimating a timing jitter sequence of the first signal under measurement as a first timing jitter sequence; a second timing jitter estimator for estimating a timing jitter sequence of the second signal under measurement as a second timing jitter sequence; and a cross-correlation coefficient estimator to which the first timing jitter sequence and the second timing jitter sequence are inputted for calculating the cross-correlation coefficient between the first and the second signals under measurement.

Claim 2

An apparatus for measuring the cross-correlation coefficient between a first and a second signals under measurement comprising: a first timing jitter estimator for estimating a timing jitter sequence of the first signal under measurement as a first timing jitter sequence; a second timing jitter estimator for estimating a timing jitter sequence of the second signal under measurement as a second timing jitter sequence; and a cross-correlation coefficient estimator to which the first timing jitter sequence and the second timing jitter sequence are inputted for calculating the cross-correlation coefficient between the first and the second signals under measurement.

Claim 8

The apparatus for measuring the cross-correlation coefficient between a first and a second signals under measurement according to any one of claims 1 - 6 wherein said timing jitter estimator comprises: an analytic signal transformer for transforming a signal under measurement into a complex analytic signal; an instantaneous phase estimator for obtaining an instantaneous phase of the analytic signal; a continuous phase converter for converting the instantaneous phase into a continuous instantaneous phase; a linear phase estimator for estimating, from the continuous instantaneous phase, its linear instantaneous phase; a subtractor for removing the linear instantaneous phase from the continuous instantaneous phase to obtain an instantaneous phase noise; and a zero-crossing sampler for sampling its input at a timing close to a zero-crossing timing of a real part of the analytic signal to output the sampled signal, said zero-crossing sampler being inserted in series to any one of connection points between said instantaneous phase estimator and said continuous phase converter, between said continuous phase converter and said linear phase estimator/said subtractor, and at an output side of said subtractor; wherein a timing jitter sequence of the clock signal under measurement is outputted as an output of said jitter sequence estimation part.

Claim 11

The apparatus for measuring the cross-correlation coefficient between a first and a second signals under measurement according to any one of claims 1 - 6 further including: a waveform clipper to which the signal under measurement is inputted for removing amplitude modulation components of the clock signal under measurement in the state that phase modulation components are retained in the signal under measurement to output the clock signal under measurement from which the amplitude modulation components have been removed to said timing jitter estimator.

Claim 12

The method of measuring the cross-correlation coefficient between a first and a second signals under measurement comprising: a step of estimating a timing jitter sequence of the first signal under measurement as a first timing jitter sequence; a step of estimating a timing jitter sequence of the second signal under measurement as a second timing jitter sequence; and a cross-correlation coefficient estimation step for calculating the cross-correlation coefficient between the first and the second signals under measurement from the first timing jitter sequence and the second timing jitter sequence.

Claim 13

The method of measuring the cross-correlation coefficient between a first and a second signals under measurement comprising: a step of estimating a timing jitter sequence of the first signal under measurement as a first timing jitter sequence; a step of estimating a timing jitter sequence of the second signal under measurement as a second timing jitter sequence; and a cross-correlation coefficient estimation step for calculating the cross-correlation coefficient between the first and the second signals under measurement from the first timing jitter sequence and the second timing jitter sequence.

Claim 19

The method of measuring the cross-correlation coefficient between a first and a second signals under measurement according to any one of claims 11 - 16 wherein said step of estimating a timing jitter sequence comprises: a step of transforming a clock signal under measurement into a complex analytic signal; a step of obtaining an instantaneous phase of the signal under measurement from the analytic signal; a step of converting the instantaneous phase into a continuous instantaneous phase; a step of estimating, from the continuous instantaneous phase, its linear instantaneous phase; a step of removing the linear instantaneous phase from the continuous instantaneous phase to obtain an instantaneous phase noise; and a step of sampling any one of the instantaneous phase, the continuous instantaneous phase, and the phase noise waveform at a timing close to a zero-crossing timing of a real part of the analytic signal; wherein a timing jitter sequence of the signal under measurement is eventually obtained.

Claim 21

The method of measuring the cross-correlation coefficient between a first and a second signals under measurement according to any one of claims 11 - 16 further including: a step of performing a waveform clipping, in the state that phase modulation components are retained in the signal under measurement, to remove amplitude modulation components of the signal under measurement, and moving to said step of estimating a timing jitter sequence.