Adaptive phase detection method and apparatus
US4138644A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1977 |
| Grant date | Feb 6, 1979 |
| Priority date | — |
| Expiry date | Nov 21, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/233
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An adaptive phase detection method and apparatus is described which provides an estimated value .phi..sub.n of the phase .phi..sub.n transmitted at a signalling instant nT in a data transmission system using a M-phase PSK modulation technique. The system compensates for the effects of the intersymbol interference created by not more than one leading lobe of a succeeding signal and an arbitrary number of trailing lobes of preceding signals caused by the impulse response of the transmission channel. The method of the present invention mainly comprises the steps of: PA1 Determining at least two residual errors, each of which is obtained by subtracting from the phase .psi..sub.n received at signalling instant nT the sum of one of the possible values which can be taken on by the transmitted signal at each signalling instant, i.e., one of the phases of the constellation, and the estimated value of the phase error due to the intersymbol interference corresponding to that phase of the constellation, PA1 Comparing the residual errors thus obtained with each other, PA1 Selecting the phase .phi..sub.n which yields the smaller of the residual errors as the most probable transmitted phase .phi.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.