| 摘要 |
PURPOSE:To realize the error rate equal to that of the analog system by using a hard discrimination digital matching filter so as to take spread synchronization and employing correlation valve between a data subjected to multi-value A/D conversion and a local signal so as to reproduce a reproduction data. CONSTITUTION:A reception signal subjected to direct spread processing by phase deflection modulation is multiplied with two orthogonal local signals at a multiplier 3, a high frequency component is eliminated by an LPF 4 and the result is converted into a base band signal. The signal is converted respectively by a multi-value A/D converter 13 and its most significant bit is inputted to a hard discrimination digital matching filter 16, from which a timing for correlation detection is extracted, a local generator 18 is reset at the timing to take spread synchronization. On the other hand, an output of the A/D converter 13 is subject to time division by a selector 17 and the result is multiplied with an output of the local generator 18 at a multiplier 19, the product is integrated and a phase is extracted by a phase detector 21 and a relevant data is outputted for discrimination. Thus, the spread synchronization is taken at a high speed without a large sized equipment and the error rate is reduced. |
