Method and device for automatic control of the frequency of a local oscillator in a DS-CDMA type receiver
US7035605B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 2003 |
| Grant date | Apr 25, 2006 |
| Priority date | — |
| Expiry date | Oct 26, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J13/0044
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method for controlling frequency of a local oscillator in a DS-CDMA type receiver includes transforming a known spread spectrum signal into a sampled digital signal formed of symbols with a despreaded frequency spectrum, and determining a residual frequency error fe for each symbol including a first residual frequency error fe1. The method further includes correcting the frequency of the local oscillator with the residual frequency errors, and determining an average of absolute values of a predetermined number of successive residual frequency errors. The average is compared with a threshold, and if the average is greater than or equal to the threshold, the local oscillator frequency is corrected using an error equal to −sgn(fe1) (1/T−|fe1|), where sgn is the sign function, | | is the absolute value function and T is duration of a symbol before determining the next residual frequency error associated with the next symbol.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.