Synchronization system for use in direct sequence spread spectrum signal receiver
US4567588A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 23, 1984 |
| Grant date | Jan 28, 1986 |
| Priority date | — |
| Expiry date | Mar 23, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J13/00
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A plurality of transmitters synchronized to a common clock each transmit a data signal spread by a common bipolar pseudo-random code having a different assigned code sequence shift. A receiver, synchronized to the clock, discriminates the signals transmitted by a predetermined transmitter from signals transmitted by the others by generating a first pseudo-random code that is a replica of the common bipolar pseudo-random code and has a code sequence shift corresponding to that of the predetermined transmitter, and a second bipolar pseudo-random code that is a replica of the common bipolar pseudo-random code and has an unassigned code sequence shift. The difference between the first and second bipolar pseudo-random code sequences, which is a trinary code sequence, is cross-correlated with the incoming signals. The cross-correlation despreads only the signal having the predetermined code sequence shift. Each receiver includes a number of correlation detectors offset from each other by a fraction of a code chip, together with decision circuitry to identify cross-correlation peaks. The cross-correlation output of a primary correlation detector generates in-phase and quadrature-phase cor…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.