Method and system for measuring signal propagation delays using ring oscillators
US6219305A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1998 |
| Grant date | Apr 17, 2001 |
| Priority date | — |
| Expiry date | Jul 14, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/318516
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A circuit measures the signal propagation delay through a selected test circuit. The test circuit is provided with an inverting feedback path so that the test circuit and feedback path together form a free-running oscillator. The oscillator then automatically provides its own test signal that includes alternating rising and falling signal transitions on the test-circuit input node. These signal transitions are counted over a predetermined time period to establish the average period of the oscillator. Finally, the average period of the oscillator is related to the average signal propagation delay through the test circuit. One embodiment of the invention includes a phase discriminator that samples the output of the oscillator and accumulates data representing the duty cycle of that signal. The duty cycle can then be combined with the average period of the test signal to determine, separately, the delays associated with falling and rising edges propagating through the test circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.