| 摘要 |
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.
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