Configurable pulse amplitude modulation clock data recovery
US9184906B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 2014 |
| Grant date | Nov 10, 2015 |
| Priority date | — |
| Expiry date | Sep 22, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/0334
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Embodiments include systems and methods for using generalized pulse amplitude modulation (PAM-X) signaling with an at-rate not-return-to-zero (NRZ) clock data recovery (CDR) system. Some implementations include dual-mode signaling for an at-rate CDR (e.g., using standard NRZ signaling at lower operating frequencies and pseudo-NRZ signaling derived from PAM-X signaling at higher operating frequencies. Embodiments derive an apparent direction of signal transition from PAM-X signaling. The direction can be used to calculate pseudo-NRZ values. For example, when the PAM-X signal transitions in an upward direction, a pseudo-current NRZ value and a pseudo-previous NRZ value of ‘−1’ and ‘+1’ can be generated, respectively. An at-rate NRZ CDR can use the pseudo-NRZ values and a derived error value to make an offset determination. The offset determination can then be used to offset a generated clock signal in the CDR system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.