Analog delay based fractionally spaced n-tap feed-forward equalizer for wireline and optical transmitters
US10243762B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 2018 |
| Grant date | Mar 26, 2019 |
| Priority date | — |
| Expiry date | Apr 16, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03509
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An analog-based architecture is used to produce tap spacings in an n-tap fractionally-spaced equalizer without the need for digital clock-driven elements. The analog voltage-controlled delay cell circuits control the amount of applied delay based on the measured phase difference between quarter-rate clock signals. Because low speed clock signals are sufficient for comparison purposes, the analog delay cells can be placed before the quarter-rate multiplexors in the data path. The use of analog-based delay cells eliminates the need to route high-speed clock signals to multiple digital delay elements that are typically used to achieve fractionally spaced data signals in n-tap FIR equalizers. Timing margin issues can also be eliminated since digital clocked elements are not used to produce the fractionally spaced delays. The analog-based delay approach also consumes less power relative equalizers that use multiple digital delay elements requiring high speed clock signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.