US 2002/0163958 A1 · Apparatus for and method of measuring jitter

Abstract

A signal under measurement x(t) is transformed into a complex analytic signal zc(t), and an instantaneous phase of the xc(t) is estimated using the zc(t). A linear phase is removed from the instantaneous phase to obtain a phase noise waveform Δ®(t) of the x(t), and the Δφ(t) is sampled at a timing close to a zero-crossing timing of the x(t) to obtain a timing jitter sequence. Then a difference sequence of the timing jitter sequence is calculated to obtain a period jitter sequence. The period jitter sequence is multiplied by a ratio T0/Tk,k+1 of the fundamental period T0 of the x(t) and the sampling time interval Tk,k+1 to make a correction of the period jitter sequence. A period jitter value of the x(t) is obtained from the corrected period jitter sequence.

Claims14

Dependent claims

An apparatus for measuring a jitter of a signal under measurement comprising:

a timing jitter estimator to which the signal under measurement is inputted for obtaining its timing jitter sequence;;
a first differentiator to which the timing jitter sequence is inputted for calculating its difference sequence to output a period jitter sequence;
a corrector part to which the period jitter sequence is inputted for multiplying the period jitter sequence by a ratio T0/Tk,k+1 of a fundamental period T0 of the signal under measurement and the approximated zero-crossing point interval Tk,k+1 to output a corrected period jitter sequence;
and
a jitter detecting part to which the corrected period jitter sequence is inputted for obtaining a jitter of the signal under measurement.

2 more elements

A method of measuring a jitter of a signal under measurement comprising:

a step of obtaining a timing jitter sequence of the signal under measurement;
a step of calculating a difference sequence of the timing jitter sequence to generate a period jitter sequence:
a step of multiplying the period jitter sequence by a ratio T0/Tk,k+1 of a fundamental period T0 and the approximated zero-crossing point interval Tk,k+1 to obtain a corrected period jitter sequence;
and
a step of obtaining a period jitter of the signal under measurement from the corrected period jitter sequence.

2 more elements

A method of measuring a jitter of a signal under measurement comprising:

a step of obtaining a timing jitter sequence of the signal under measurement;
a step of calculating a difference sequence of the timing jitter sequence to generate a period jitter sequence:
a step of multiplying the period jitter sequence by a ratio T0/Tk,k+1 of a fundamental period T0 and the approximated zero-crossing point interval Tk,k+1 to obtain a corrected period jitter sequence;
a step of calculating a difference sequence of the corrected period jitter sequence to generate a cycle-to-cycle period jitter sequence:
and a step of obtaining a cycle-to-cycle period jitter of the signal under measurement from the cycle-to-cycle period jitter sequence.

2 more elements

Dependencies are inferred from the claim text.

Apparatus for and method of measuring jitter

Life of this patent

Apparatus for and method of measuring jitter

Life of this patent

Abstract

Claims14