| 摘要 |
PROBLEM TO BE SOLVED: To obtain stable reception characteristics by holding synchronization of reproduction of a carrier wave even at low C/N by reproducing the carrier wave by a signal in a specified modulation system. SOLUTION: An inputted signal from a high frequency input terminal 10 is selected, is converted into a digital signal, is digitally demodulated by a Costas loop 61, the modulated signal is inputted in a unique word detecting circuit 6, a unique word is detected the timing of transmission multiplex control information and that of a burst signal are decided and a pulse signal is generated from a timing generator 19a. In addition, a demodulated signal is decoded by a Viterbi/trellis decoding 7, the timing of a BPSK modulation signal in a transmission main signal is determined by a transmission multiplex control information which is decoded by transmission multiplex control information decoding 8 and a pulse signal is generated from a timing generator 29b. The pulse signal is added by an adder 10, a Costas loop opening/closing switch 5 is closed in binary phase modulation (BPSK) signal period, transmission multiplex control information period, burst signal period and the carrier wave reproduction is performed. |
