| 摘要 |
PURPOSE:To obtain a digital demodulation system including a transversal equalizer and a demodulator playing a sufficient role of equalization capability by discriminating whether or not each signal point of a multi-value digital modulation wave is included in a predetermined region in response to the signal point arranging state. CONSTITUTION:Region discrimination circuits 35a, 35b, 36a, 36b and storage circuits 53-68 prevent malfunction. The region discrimination circuits 35a, 35b discriminate the outermost region A and the innermost region A' on a diagonal line, and when signals a1-a4 are subject to interference of common mode and same polarity and signals a13-a16 are subject to interference of common mode but opposite polarity signal, the circuits output a clock pulse. Then outputs a of EX-OR circuits 37-44 are read by D flip-flops 53-60. Since the region discrimination circuits 35a, 35b hold the preceding information when the output of the circuits does not exist, an error signal from a signal only entering the regions A, A' is obtained from the outputs of the flip-flops 53-60. |
