| 摘要 |
PROBLEM TO BE SOLVED: To provide a PN code synchronization device that can more quickly and surely acquire a synchronizing signal. SOLUTION: A transmission epoch denoting a head of a spread code at a transmission side of a modulation section 1 is synchronously with a timing of an inverse spread signal generated from an inverse signal generator 700 of a demodulation section 2 and the generator 700 outputs an inverse spread signal whose timing is coincident with the synchronized timing. A correlation value detector 400 outputs a shift control signal that shifts a phase of the inverse spread signal to detect a correlation between the received spread signal and the inverse spread signal whose phase is shifted by a spread phase shift circuit 800, and a synchronization discrimination device 500 discriminates the synchronization based on a level of the output correlation. Since a time of a radio wave returning to a ground station from a satellite is known in advance, the time is held and the initial phase of a PN code is captured before and after the known time to attain the capture in a short time in the unit of bits. |
