Apparatus for and method of measuring a peak jitter
US6460001B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 2000 |
| Grant date | Oct 1, 2002 |
| Priority date | — |
| Expiry date | Mar 29, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/205
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
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 &Dgr;&phgr;(t). A peak value &Dgr;&phgr;max of absolute values of the &Dgr;&phgr;(t) is obtained, and 4&Dgr;&phgr;max is defined as the worst value of period jitter of the input signal. The &Dgr;&phgr;(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(−(2&Dgr;&phgr;max)2/(2&sgr;j2)) is calculated from the mean-square value &sgr;j and 2&Dgr;&phgr;max, and the calculated value is defined as a probability that a period jitter exceeds 2&Dgr;&phgr;max.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.