Combined coherent frequency and phase shift keying modulation system
US4290140A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 21, 1979 |
| Grant date | Sep 15, 1981 |
| Priority date | — |
| Expiry date | Jun 21, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/02
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A system of modulation and demodulation for the transmission of binary data in the presence of multipath. The binary data modulates the phase of the carrier and the same binary data, after a delay of ".delta." bits, also modulates the frequency of the carrier. Following reception, the binary data is obtained either by frequency demodulation or by a method of coherent phase shift demodulation wherein the mark or the space frequency is selected for detection of each bit in accord with the bit received "n" bits previously. The system selects between the demodulation methods to obtain one which operates satisfactorily in the instant electromagnetic environment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.