| 摘要 |
PURPOSE:To perform data communication of higher reliability and to increase the number of times of multiplexing by simplifying the signal processing of the base band system in a reception part, and performing frequency offset compensation in a direct spread spectrum communication using the multilevel phase modulation system. CONSTITUTION:The data string to be encoded for each symbol in the multilevel phase modulation system is subjected to DBPSK modulation in a DBPSK modulation part 102 by carrier frequencies of respective phases, and results are synthesized and transmitted; and on the reception side, respective data strings are subjected to BPSK delay detection by a BPSK delay detection part 122, and the data string is decoded by these outputs. The extent of frequency offset can be obtained from the correlator output to correct the frequencies of reception local oscillators 115 and 119, and this system can be combined with the processing, which compensates phase rotation of data at the time of decoding, or the means which adds outputs of pairing correlators to perform decoding. |
