Digital downconverter/despreader for direct sequence spread spectrum communications system
US5640416A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Jun 17, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/7085
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A digital despreader and downconversion technique useful for spread spectrum communications receivers digitally tracks a timing phase of a PN sequence without the need for steering an external hardware clock. An additional benefit of the technique is the use of a receive filter matched to the bandlimited transmit chip sequence prior to despreading which reduces the amount of noise present after despreading. A narrowband filter also permits the use of a single A/D converter in the receiver, IF sampling at a relatively low sample rate compared to other techniques. A method for reducing a total number of computations required thereby facilitating implementation in a single custom digital integrated circuit is also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.