QAM with DC bias in one channel
US4581748A · kind A · utility
9Cited by
3References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1983 |
| Grant date | Apr 8, 1986 |
| Priority date | — |
| Expiry date | Dec 28, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/362
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A radio communication system includes a transmitter unit, a transmission line, and a receiver unit. The transmitter unit modulates an in-phase-channel (I-ch) data signal and quadrature-channel (Q-ch) data signal with two carriers having a .pi./2 phase difference with each other. A DC offset is added to either one of the I-ch and Q-ch data signals before they are modulated. In the receiver unit, a demodulation operation is performed, for the received transmission signal, by a synchronous detection with the use of a leakage carrier created due to the DC offset and included in the transmission signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.