| 摘要 |
<p>PROBLEM TO BE SOLVED: To receive the signals of a synchronous modulation part also by a mobile object and to improve the receiving quality of a differential modulation part by correcting the phases and amplitudes of symbols other than its own one in a frame and demodulating coherently the corrected output. SOLUTION: A controller 2 of a synchronous modulation part stores the output received from an orthogonal frequency division multiplexing(OFDM) demodulation part 1 in a frame memory 3 in an amount equivalent to one frame. A compensating device 4 estimates and corrects with internal extraction the phase of a symbol of a prescribed part according to a symbol whose phase and amplitude are known and applies the corrected phase to an entire frame. The symbols equivalent to four symbol strings having new times are stored in a partial frame memory 5 among all symbols of a single frame. The corrected symbol is demodulated at a synchronous carrier coherent demodulation part 6 and then outputted. A controller 9 of a differential modulation part stores the output received from the pat 1 in a symbol memory 7 in an amount equivalent to a single symbol string, and the output of the part 1 equivalent to one symbol is corrected by a compensating device 8. Then the symbol is inputted to a differential carrier coherent demodulation part 10 to be demodulated there and then outputted.</p> |
