Adaptive equalizer with enhanced error quantization
US6418164B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 1999 |
| Grant date | Jul 9, 2002 |
| Priority date | — |
| Expiry date | Jan 14, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03624
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An adaptive equalizer for use in blind equalization systems to compensate for transmission channel distortion and noise in a digital communication system uses multiple quantization levels for implementation of the Constant Modulus Algorithm (CMA). Different quantization levels are used in different regions of the CMA error function for both passband and baseband equalizers. In one embodiment, a quantizer with a step rise having logarithmic scale is used to digitize the CMA error function. In particular, a quantizer with a step rise in which each level of the quantizer step rise is a power of 2 is used to digitize the CMA error function. In another embodiment, a quantizer with a step rise in which each level of the quantizer step rise is the sum of two or more logarithmic scales is used to digitize the CMA error function. In particular, a quantizer with a step rise wherein each level of the quantizer step rise is the sum of two or more numbers each of which is a power of 2 is used to digitize the CMA error function. The use of logarithmic scales, the sum of logarithmic scales, powers of 2, or the sum of powers of 2 for the quantizer step rise size to digitize the CMA error function …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.