Differential correlator for spread spectrum communication system
US4964138A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 1988 |
| Grant date | Oct 16, 1990 |
| Priority date | — |
| Expiry date | Nov 15, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/70718
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A spread spectrum communications system includes an encoder for differentially encoding a spread spectrum spreading code sequence in accordance with an input data signal. Each chip of the spreading code sequence is inverted, or not inverted, relative to the polarity of a corresponding chip of the spreading code sequence a fixed time delay previously, depending on whether the input data is a logic one or zero, respectively. At the receiver, the data is recovered in a differential data decoder wherein the presently received chip of the spread spectrum signal and a corresponding previously received chip of spread spectrum signal, received a fixed time delay previously, are compared one chip at a time. Since it is the spreading code sequence that is differentially encoded and differentially decoded, there is no need for a synchronized code sequence generator at the receiver, and data synchronization is achieved after one cycle time of the received spread spectrum spreading code sequence has elapsed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.