| 摘要 |
PURPOSE: To improve efficiency of demodulation processing with simple constitution by determining a symbol discrimination point on the basis of the time when the correlation value detected sequentially by a correlation calculating means has a maximum value. CONSTITUTION: A demodulated signal (b) outputted from each base-band filter 16 is inputted to a symbol extracting circuit 17 corresponding to a subcarrier and the circuit 17 specifies a discrimination point (d). The amplitude detection part 21 of a circuit 20 detects the amplitude of the composite signal of an in-phase component I(t) outputted from a circuit 12 and the subcarrier consisting of an orthogonal component Q(t). Further, a reference amplitude storage means 23 stores a reference amplitude nearly equal to the amplitude of the reference symbol part included in a received signal and the correlation value between the amplitude detected by the correlation detecting means 22 and the reference amplitude is found in sequence. On the basis of the time when the correlation value reaches the maximum value, a discrimination point determining means 24 determines it as a symbol discrimination point (d) and sends it out to the circuit 17. Then the circuit 17 extracts the position that the discrimination point (d) specifies among respective demodulated signals (b) and outputs it as a final demodulation symbol (c). |
