Detection of frequency differences between signals
US6680991B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 1, 2002 |
| Grant date | Jan 20, 2004 |
| Priority date | — |
| Expiry date | Oct 1, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/095
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A lock detector is described for detecting a difference between the frequencies of a first and a second input signal. The lock detector includes first and second beat generators configured to generate corresponding beat signals based on the first and second input signals. The second beat signal is phase shifted relative to the first beat signal. A chatter elimination module combines the two chattery beat signals to produce a third corresponding beat signal that is substantially free of chatter. Using this clean beat signal and either of the input signals, a lock detection module produces a lock detection signal, which indicates whether the difference between the frequencies of the first and second input signals is within a prescribed tolerance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.