Self-adaptive equalizer circuit for a differentially coherent demodulation installation
US5027371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1989 |
| Grant date | Jun 25, 1991 |
| Priority date | — |
| Expiry date | Dec 29, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03038
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A self-adaptive equalizer circuit for a receive using differential demodulation, and in particular for a receiver using a plurality of paths in diversity (1, 2). For each diversity path (1, 2) there is a self-adaptive filter (18, 19) placed before the differential demodulation. The coefficients (CO to Cn) of the filter are updated at each instant KT, where T is the symbol rate period, using the formula: EQU Ci(k)=Ci(k-1)-.mu.. y(k-1). x(k-1)* . e(k) where .mu. is a real number much less than 1, e.g. equal to 0.001, where Ci(k) is the value given to the coefficient (Ci) at instant kT; Ci(k-1) is the value taken by the same coefficient Ci at the instant (k-1)T; y(K-1) is the output signal from the self-adaptive filter, the symbol being sampled at the symbol rate of period T; x(k-i)* is the complex conjugate value of the sample x(k-i) present in the filter at said instant kT and relating to the coefficient Ci; and e(k) is the above-mentioned error at the instant kT.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.