System for detecting digital data transmitted by modulating a carrier
US4024342A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1975 |
| Grant date | May 17, 1977 |
| Priority date | — |
| Expiry date | Nov 6, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/38
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A data transmitting and receiving system in which data is transmitted by varying the phase and amplitude of a carrier, including a receiver which detects the data in a received signal while reducing the effects of noise components which alter the phase and amplitude of the received signal. An in-phase component and a quadrature component are derived from the received signal and are then rotated an angular amount which is a function of an estimated value of the phase error in the received signal. The rotated components are then compared with two sets of reference coordinates for selecting a pair of reference coordinates which have values closest to the values of the rotated in-phase and quadrature components, respectively. The estimated value of the phase error is derived as a trigonometric function of the rotated components and selected reference coordinates. The selected reference coordinates are indicative of the transmitted data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.