Digital radio communication system utilizing quadrature modulated carrier waves
US4817116A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1985 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Apr 12, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2334
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In order to achieve the spectrum economy and reduce the power consumption of a transmitter and reduce the error rate at a receiver and simplify receiver circuitry, at least one bit stream to be transmitted is quadrature modulated in a manner that the signal points do not define a trace on a complex amplitude plane which passes through the origin of the plane coordinates or in the vicinity thereof. The received signal is hard limited and frequency-discriminated to determine the instantaneous angular velocity of the received signal and is integrated to detect the phase variation between two consecutive received signals, and thereafter is decided with respect to the phase variation according to the decision threshold levels 0 and .+-..pi. radians.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.