| 摘要 |
PROBLEM TO BE SOLVED: To shorten a preamble period and arithmetic processing time by detecting a frequency offset value and estimating transmission line characteristics by using the same preamble signal at the time of obtaining the frequency offset value and the transmission line characteristics in the preamble period, operating a phase rotation means and equalizing reception signals. SOLUTION: A/D converters 11 and 12 ADD-convert the reception signals I and Q, a memory part 13 fetches them for an optional period and controls output and a phase rotation part 14 performs rotation by a required phase portion. By an average phase difference obtained by an average value detection circuit 16 from a phase difference detected by a phase difference detection circuit 15, an integration circuit 17 and a vector transformation circuit 18 rotate the phase of the phase rotation part 14. From the transmission line characteristics during the preamble period obtained by using the signals after the phase is rotated in the phase rotation part 14 by a transmission line characteristic estimation part 19, a tap coefficient setting part 20 sets the tap coefficient of an equalizer 21. Thus, the equalizer 21 equalizes and demodulates the output of the phase rotation part 14 and the preamble period is shortened. |
