Placement of a transmit predistortion filter with respect to a data access arrangement
US6674856B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 23, 1999 |
| Grant date | Jan 6, 2004 |
| Priority date | — |
| Expiry date | Sep 23, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/68
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The present invention provides a digital pre-distortion filter in arrangement with a data access arrangement (DAA) on the component side (e.g., in a modem chipset). This arrangement of the pre-distortion filter outside of the DAA allows digital processes such as digital emulation of the central office impedance to remain unaffected by the pre-distortion in the transmitted signal, allowing the dynamic range of the transmitted signal to be flattened to minimize return loss without complicating the transfer function of the digital emulation of the central office complex load. In the case of a digital emulation filter, placement of a digital pre-distortion filter outside of an analog-to-digital (A/D) digital-to-analog (D/A) loop also minimizes the noise otherwise associated with the use of a pre-distortion filter. Thus, benefits of a pre-distortion filter can be gained without interfering with emulation of impedance, and without causing a significant amount of noise in the transmitted signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.