Apparatus for and method of measuring a jitter
AssigneesAdvantest Corporation, Mani Soma
InventorsTakahiro Yamaguchi, Mani Soma, Masahiro Ishida, Yasuo Furukawa, Toshifumi Watanabe
Life of this patent
Estimating the term…
Abstract
A clock waveform XC(t) is transformed into a complex analytic signal using a Hilbert transformer and an instantaneous phase of this analytic signal is estimated. A linear phase is subtracted from the instantaneous phase to obtain a varying term Δφ(t). A difference between the maximum value and the minimum value of the varying term Δφ(t) is obtained as a peak-to-peak jitter, and a root-mean-square of the varying term Δφ(t) is calculated to obtain an RMS jitter.
Claims22
An apparatus for measuring a jitter comprising:
- analytic signal transforming means for transforming a digital clock signal into a complex analytic signal;
- instantaneous phase estimating means for obtaining an instantaneous phase of the analytic signal;
- linear phase removing means for removing a linear phase from the instantaneous phase to obtain a phase noise waveform;
- and
- jitter detecting means for obtaining a jitter of the clock signal from the phase noise waveform.
An apparatus for measuring jitter of a clock signal comprising:
- analytic signal transforming means for transforming a clock signal into an analytic signal;
- instantaneous phase estimation means for estimating an instantaneous phase of the analytic signal;
- varying term estimation means for estimating a varying term of the instantaneous phase;
- and
- jitter detection means for detecting jitter of the clock signal from the varying term of the instantaneous phase.
A method for measuring jitter of a clock signal comprising the steps of:
- transforming the clock signal into an analytic signal;
- estimating an instantaneous phase of the analytic signal;
- estimating a varying term of the instantaneous phase;
- and
- detecting jitter of the clock signal from the varying term of the instantaneous phase.
A method for measuring jitter of a clock signal comprising the steps of:
- comparing the clock signal with reference analog values to obtain a digital clock signal;
- transforming the digital clock signal into an analytic signal;
- estimating an instantaneous phase of the analytic signal;
- estimating a varying term of the instantaneous phase;
- and
- detecting jitter of the analog clock signal from the varying term of the instantaneous phase.
Dependencies are inferred from the claim text.