Method and apparatus for differential detection of a unique word and demodulation with the use of differential detection of a unique word

摘要

PROBLEM TO BE SOLVED: To detect an unique word(UW) by enlarging a measurement range while the resolution of the carrier frequency offset of a quasi-synchronization detecting signal is kept small and also keeping position detecting precision high. ;SOLUTION: In an initial acquisition mode, a UW delay detecting circuit 4 with a delay symbol number N(0.5N≤1) and the UW delay detecting circuit 7 with the delay symbol number N/2 are used so as to generate the UW detecting signal S5 of the quasi-synchronization detecting signal S2 and frequency offset information S8. Frequency offset information S8 reduces the frequency offset of the quasi-synchronization detecting signal S10 for demodulating a data signal. Then, the mode becomes a slight tuning acquisition mode, the UW delay detecting circuit 13 with the delay symbol number M(1M) is operated. When UW is detected from the quasi-synchronization detecting signal S11, the circuit 13 generates the UW detecting signal S5 and the double- check UW detecting signal S13.;COPYRIGHT: (C)1998,JPO