| 摘要 |
PURPOSE:To introduce a differential code and to completely remove a phase ambiguity without deteriorating an error correcting capacity by inputting the output signal of a phase demodulating circuit to an error correcting circuit, outputting a signal to discriminate that the phase ambiguity is present and inputting the output signal of the error correcting circuit to a differential logical circuit. CONSTITUTION:The ambiguity equivalent to a phase angle 180 deg. can be removed by inputting the output value of a phase demodulating circuit 3 to an error correcting circuit 5 and observing a likelihood signal to occur in the internal part of a decoding circuit 52. The code to decide the phase ambiguity, which cannot be removed by an error correcting circuit 5, is inputted to a differential logical circuit 6 and either of the correct code or the inversion of '1' and '0' codes is obtained. Thus, the ambiguity can be removed by the differential logical circuit 6. |
