Carrier-modulation data transmission equalizers
US3947768A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 8, 1975 |
| Grant date | Mar 30, 1976 |
| Priority date | — |
| Expiry date | Jan 8, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/01
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The feature of the invention is an adaptive equalizer for modulated carrier transmission systems in which a received signal is subjected to a Hilbert transformation to obtain a second signal having a 90.degree. phase shift for all components. The two signals are then passed through a pair of filters each and the outputs are cross-combined to generate the cartesian coordinate signals of an equalized signal. The coordinate signals are combined in a polar converter and are then decoded to detect the amplitude and phase data components of the received signal. The equalizers are made adaptive by determining at each sampling time, the phase and amplitude errors in the signal and using these errors to modify the coefficients of the equalizing filters. The phase and amplitude errors are recoded into Cartesian coordinates and multiplied by the values of the samples at each tap of the filters to generate four error signals for each tap. A cross combination of these signals is time averaged and used to adjust the corresponding coefficients at the associated taps of the equalizer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.