| 摘要 |
PURPOSE:To constitute a demodulating circuit of general-purpose circuit elements by using a modulation signal the smallest in phase difference among those produced with the same frequency and a fixed phase difference, to perform the PSK or DPSK demodulation. CONSTITUTION:A phase comparator 3, LPF4, VCO5, counter 10 and a counter 6 form a PLL, then a signal generating means which produces signals F, G, H and I the same in frequency as a signal A (PSK or DPSK modulation signal) and different in phase. A circuit consisting of EXOR11-14, LPF16-20, comparators 21-24 and EXOR25-28 detects a signal that is most suited to demodulation out of those signals F-I. A circuit consisting of EXOR11-14, LPF17-20, comparators 29-32 and a decoder 9 uses the signal selected by a selection circuit consisting of a latch circuit 38, AND gates 33-36 and an OR gate 37 to demodulate the PSK or DPSK modulation signal. |
