| 摘要 |
<p>PROBLEM TO BE SOLVED: To estimate both carrier frequency errors and sampling frequency errors in a fast process, and to prevent increase of the arithmetic error due to interference of an adjacent data carrier unlike the case where a pilot carrier is used. SOLUTION: The real and imaginary parts of result of FET of continuous two preamble symbols are supplied to a tan-1 calculation part 21, where the phase change is calculated for each carrier frequency. The carrier frequency errors are calculated by subtracters 25 and 26, an adder 27 and multiplier 28, and the frequency areas are averaged by an accumulator 29 and a multiplier 30. Thus, the presumed value of carrier frequency error is obtained. In an averaging mode, the carrier frequencies which are selected in the order of higher power levels are used. Then the sampling frequency errors are calculated by subtracters 25, 26 and 31 and a multiplier 32, and the frequency areas are averaged by an accumulator 33 and a multiplier 34.</p> |
