Modulation apparatus of multicarrier direct sequence spread spectrum communication system
US6411645B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 1998 |
| Grant date | Jun 25, 2002 |
| Priority date | — |
| Expiry date | Aug 20, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/026
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a signal modulation apparatus of multicarrier direct sequence spread spectrum communication system. There was a problem that since multiple carrier having different frequencies are modulated by a baseband signal and the results are added to be transmitted, the enveloped variation of transmitted signal is very large. A modulation apparatus of multicarrier direct sequence spread spectrum system is suggested to solve such problems, which can reduce the enveloped variation of transmitted signal by inverting the polarity of baseband signal which modulates one of four carriers in the case when the same baseband signal is used to modulate the multiple carriers and by inverting the plurality of one of two Walsh code pairs having two adjacent indexes by using the characteristics of Walsh function in case when different baseband signals should be used to modulate four carriers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.