Channel equalization apparatus and method using the Fourier transform technique
US4152649A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 21, 1977 |
| Grant date | May 1, 1979 |
| Priority date | — |
| Expiry date | Jun 21, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03038
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method of and apparatus for determining during an initial training period the initial values of the coefficients of a transversal equalizer in a data transmission system in which the transmission channel creates frequency shift. The received periodic training sequence is modulated by a time-domain window signal whose Fourier transform exhibits a relatively flat central peak and has comparatively low values in the vicinity of those frequencies which are a multiple of the inverse of the period of the transmitted sequence, and the discrete Fourier transform W.sub.k of the modulated signal is computed. The values of the coefficients of the equalizer are obtained by computing the inverse discrete Fourier transform of the ratio F.sub.k =Z.sub.k /W.sub.k, where Z.sub.k is the discrete Fourier transform of the transmitted sequence.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.