| 摘要 |
PURPOSE:To realize quick leading-in of an ACT demodulator by using the phase measured value obtained by control phase quantization to constitute a kind of a base band delay detector and leading in a BTR by the detection output of this detector. CONSTITUTION:Delay detecting operation is performed by a base band delay detector 3 to extract correct symbol clock information regardless of the use of the measured phase value based on a free-running carrier. That is, the component of the phase difference between transmission and reception carriers is eliminated by subtracting operation because this phase difference is regarded as scarecely changed in about a symbol time. Therefore, the data change point of the delay detecting operation result has a correct clock component independently of the symbol synchronism of a BTR 2 and the state of carrier tracking of an ACT 1. Then, its edge is used to initially lead in the BTR 2, thereby realizing quick leading-in. When the symbol synchronism is established, the ACT demodulator completes carrier tracking in the next one-symbol time, and correct demodulating operation is possible. Thus, quick leading-in of the ACT demodulator is realized. |
