| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission/reception system by which a problem that the transmission information quantity cannot be increased in a limited frequency range in a transmitter transmitting a digital signal can be solved, and which can transmit much more information in the same frequency band. SOLUTION: A transmitter 1 transmits a modified m-value QAM modulation signal obtained by assigning n-value data of a first data stream to a signal point group resulting from grouping signal points on a signal space diagram denoting an n-value first data stream, a p-value second data stream and a third data stream through a modulator 4 for m-value QAM modulation. A demodulator 25 of a first receiver 23 demodulates the n-value first data stream, a second receiver 33 demodulates the first data stream and the second data stream, and a third receiver 43 demodulates the first data stream, the second data stream and the third data stream. Thus, the receiver having only an n-value demodulation capability (n<m) in the case of receiving the m-value modified multi-value modulation wave can demodulate data of the n-value first data stream in the transmission reception system.
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