Frequency shift detection circuit with selectable granularity
US6011412A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1998 |
| Grant date | Jan 4, 2000 |
| Priority date | — |
| Expiry date | May 1, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D13/004
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency shift detection circuit for detecting a frequency shift between a first signal and a second signal includes two or more delay circuits coupled to one another in series and two or more comparison logic circuits. The first delay circuit in the series receives one of the first and second signals and produces a delayed replica. Each of the other delay circuits receives the delayed replica produced by the previous delay circuit in the series and produces a further delayed replica. Thus, the signal produced by each delay circuit is delayed from the original signal by a different amount. Each comparison logic circuit receives one of the delayed replicas and receives the other one of the first and second signals, i.e., the one that is not received by the delay circuits. In response, the comparison logic circuit produces a frequency shift detection signal when it detects a phase difference between that other one of said first and second signals and the delayed replica. By selecting or tapping one of the outputs of the comparison logic circuits, a user can select the detection granularity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.