QPSK/QBL-MSK waveform enhancement
US5818867A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1996 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Sep 9, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2014
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A modulator device is disclosed for a spread spectrum communication system which generates a modulated signal from incoming data. The device includes a QPSK portion for separating the incoming data into two data channels and for further spreading the two channels over a wide bandwidth according to a predetermined spreading code. A phase mapping element coupled to the QPSK portion for processing both channels in order to minimize spectral regrowth of the modulated signal by preventing the RF envelope deviation from going close to zero. Pulse shaping elements coupled to the phase mapping element for further processing each channel in order to improve the modulator spectral efficiency and minimize adjacent channel interference. A quad-mixer coupled to the pulse shaping elements for combining both channels into a recombined signal and for further modulating the recombined signal according to a predetermined carrier frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.