Apparatus for and method of measuring a peak jitter

摘要

An input clock signal is transformed into a complex analytic signal zc(t) by an analytic signal transforming means 13 and an instantaneous phase of its real part xc(t) is estimated using the analytic signal zc(t). A linear phase is removed from the instantaneous phase to obtain a phase noise waveform DELTAphi(t). A peak value DELTAphimax of absolute values of the DELTAphi(t) is obtained, and 4DELTAphimax is defined as the worst value of period jitter of the input signal. The DELTAphi(t) is sampled at a timing close to a zero-crossing point of the xc(t) to extract the sample value. A differential between adjacent samples is obtained in the sequential order to calculate a root-mean-square value of the differentials (period jitters). An exp(-(2DELTAphimax)2/(2sigmaj2)) is calculated from the mean-square value sigmaj and 2DELTAphimax, and the calculated value is defined as a probability that a period jitter exceeds 2DELTAphimax.