Apparatus for and method of detecting a delay fault
US6291979A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1999 |
| Grant date | Sep 18, 2001 |
| Priority date | — |
| Expiry date | Feb 16, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R25/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
There is provided a method of and an apparatus for detecting delay faults in phase-locked loop circuits. A frequency impulse is applied to a phase-locked loop circuit under test as the reference clock, and a waveform of a signal outputted from the phase-locked loop circuit under test is transformed to an analytic signal to estimate an instantaneous phase of the analytic signal. A linear phase is estimated from the estimated instantaneous phase, and the estimated linear phase is removed from the estimated instantaneous phase to obtain a fluctuation term of the instantaneous phase. A delay time is measured from this fluctuation term of the instantaneous phase, and further, a delay fault is detected by comparing a time duration during which the phase-locked loop circuit remains in a state of oscillating a certain frequency with a time duration during which a fault-free phase-locked loop circuit remains in a state of oscillating that certain frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.